sfrench/cifs-2.6.git
19 months agoMerge tag 'drm-next-2018-12-27' of git://anongit.freedesktop.org/drm/drm
Linus Torvalds [Sat, 29 Dec 2018 03:57:29 +0000 (19:57 -0800)]
Merge tag 'drm-next-2018-12-27' of git://anongit.freedesktop.org/drm/drm

Pull more drm updates from Dave Airlie:
 "Daniel collected a couple of pulls after I want on holidays, back for
  a couple of days, so may as well send them out.

  This has exynos and etnaviv work for 4.21.

  exynos:
   - plane alpha and blending configurability

  etnaviv:
   - mostly cleanups in prep for new features"

* tag 'drm-next-2018-12-27' of git://anongit.freedesktop.org/drm/drm:
  drm/etnaviv: remove lastctx member from gpu struct
  drm/etnaviv: replace header include with forward declaration
  drm/etnaviv: remove unnecessary local irq disable
  drm/exynos: fimd: Make pixel blend mode configurable
  drm/exynos: fimd: Make plane alpha configurable
  drm/etnaviv: Replace drm_dev_unref with drm_dev_put
  drm/etnaviv: consolidate hardware fence handling in etnaviv_gpu
  drm/etnaviv: kill active fence tracking

19 months agoMerge tag 'hwmon-for-v4.21' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck...
Linus Torvalds [Sat, 29 Dec 2018 03:48:25 +0000 (19:48 -0800)]
Merge tag 'hwmon-for-v4.21' of git://git./linux/kernel/git/groeck/linux-staging

Pull hwmon updates from Guenter Roeck:
 "The big change in this series is for the most part automatic:
  Introducing SENSOR[_DEVICE]_ATTR_{RO,RW,WO} variants and conversion of
  various drivers to use it. This is similar to DEVICE_ATTR variants.

  Other than that, we have

   - Some conversions of S_<PERMS> with octal values, also automated

   - Added support for Hygon Dhyana CPUs to k10temp driver

   - Added support for STLM75 to lm75 driver

   - B57891S0103 to ntc_thermistor

   - Added pm-runtime support to ina3221 driver

   - Support for PowerPC On-Chip Controller (OCC)

   - Various minor bug fices and improvements"

* tag 'hwmon-for-v4.21' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging: (80 commits)
  hwmon: (lm80) fix a missing check of bus read in lm80 probe
  hwmon: (lm80) fix a missing check of the status of SMBus read
  hwmon: (asus_atk0110) Fix debugfs_simple_attr.cocci warnings
  hwmon: (ftsteutates) Use permission specific SENSOR[_DEVICE]_ATTR variants
  hwmon: (fschmd) Use permission specific SENSOR[_DEVICE]_ATTR variants
  hwmon: (emc6w201) Use permission specific SENSOR[_DEVICE]_ATTR variants
  hwmon: (emc2103) Use permission specific SENSOR[_DEVICE]_ATTR variants
  hwmon: (emc1403) Use permission specific SENSOR[_DEVICE]_ATTR variants
  hwmon: (ds620) Use permission specific SENSOR[_DEVICE]_ATTR variants
  hwmon: (ds1621) Use permission specific SENSOR[_DEVICE]_ATTR variants
  hwmon: (dell-smm-hwmon) Use permission specific SENSOR[_DEVICE]_ATTR variants
  hwmon: (da9055-hwmon) Use permission specific SENSOR[_DEVICE]_ATTR variants
  hwmon: (da9052-hwmon) Use permission specific SENSOR[_DEVICE]_ATTR variants
  hwmon: (coretemp) Replace S_<PERMS> with octal values
  hwmon: (asus_atk0110) Replace S_<PERMS> with octal values
  hwmon: (aspeed-pwm-tacho) Use permission specific SENSOR[_DEVICE]_ATTR variants
  hwmon: (applesmc) Replace S_<PERMS> with octal values
  hwmon: (amc6821) Use permission specific SENSOR[_DEVICE]_ATTR variants
  hwmon: (adt7x10) Use permission specific SENSOR[_DEVICE]_ATTR variants
  hwmon: (adt7475) Use permission specific SENSOR[_DEVICE]_ATTR variants
  ...

19 months agoMerge tag 'vfio-v4.21-rc1' of git://github.com/awilliam/linux-vfio
Linus Torvalds [Sat, 29 Dec 2018 03:41:58 +0000 (19:41 -0800)]
Merge tag 'vfio-v4.21-rc1' of git://github.com/awilliam/linux-vfio

Pull VFIO updates from Alex Williamson:

 - Replace global vfio-pci lock with per bus lock to allow concurrent
   open and release (Alex Williamson)

 - Declare mdev function as static (Paolo Cretaro)

 - Convert char to u8 in mdev/mtty sample driver (Nathan Chancellor)

* tag 'vfio-v4.21-rc1' of git://github.com/awilliam/linux-vfio:
  vfio-mdev/samples: Use u8 instead of char for handle functions
  vfio/mdev: add static modifier to add_mdev_supported_type
  vfio/pci: Parallelize device open and release

19 months agoMerge branch 'akpm' (patches from Andrew)
Linus Torvalds [Sat, 29 Dec 2018 00:55:46 +0000 (16:55 -0800)]
Merge branch 'akpm' (patches from Andrew)

Merge misc updates from Andrew Morton:

 - large KASAN update to use arm's "software tag-based mode"

 - a few misc things

 - sh updates

 - ocfs2 updates

 - just about all of MM

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (167 commits)
  kernel/fork.c: mark 'stack_vm_area' with __maybe_unused
  memcg, oom: notify on oom killer invocation from the charge path
  mm, swap: fix swapoff with KSM pages
  include/linux/gfp.h: fix typo
  mm/hmm: fix memremap.h, move dev_page_fault_t callback to hmm
  hugetlbfs: Use i_mmap_rwsem to fix page fault/truncate race
  hugetlbfs: use i_mmap_rwsem for more pmd sharing synchronization
  memory_hotplug: add missing newlines to debugging output
  mm: remove __hugepage_set_anon_rmap()
  include/linux/vmstat.h: remove unused page state adjustment macro
  mm/page_alloc.c: allow error injection
  mm: migrate: drop unused argument of migrate_page_move_mapping()
  blkdev: avoid migration stalls for blkdev pages
  mm: migrate: provide buffer_migrate_page_norefs()
  mm: migrate: move migrate_page_lock_buffers()
  mm: migrate: lock buffers before migrate_page_move_mapping()
  mm: migration: factor out code to compute expected number of page references
  mm, page_alloc: enable pcpu_drain with zone capability
  kmemleak: add config to select auto scan
  mm/page_alloc.c: don't call kasan_free_pages() at deferred mem init
  ...

19 months agoMerge tag 'mmc-v4.21' of git://git.kernel.org/pub/scm/linux/kernel/git/ulfh/mmc
Linus Torvalds [Sat, 29 Dec 2018 00:52:18 +0000 (16:52 -0800)]
Merge tag 'mmc-v4.21' of git://git./linux/kernel/git/ulfh/mmc

Pull MMC updates from Ulf Hansson:
 "This time, this pull request contains changes crossing subsystems and
  archs/platforms, which is mainly because of a bigger modernization of
  moving from legacy GPIO to GPIO descriptors for MMC (by Linus
  Walleij).

  Additionally, once again, I am funneling changes to
  drivers/misc/cardreader/* and drivers/memstick/* through my MMC tree,
  mostly due to that we lack a maintainer for these.

  Summary:

  MMC core:
   - Cleanup BKOPS support
   - Introduce MMC_CAP_SYNC_RUNTIME_PM
   - slot-gpio: Delete legacy slot GPIO handling

  MMC host:
   - alcor: Add new mmc host driver for Alcor Micro PCI based cardreader
   - bcm2835: Several improvements to better recover from errors
   - jz4740: Rework and fixup pre|post_req support
   - mediatek: Add support for SDIO IRQs
   - meson-gx: Improve clock phase management
   - meson-gx: Stop descriptor on errors
   - mmci: Complete the sbc error path by sending a stop command
   - renesas_sdhi/tmio: Fixup reset/resume operations
   - renesas_sdhi: Add support for r8a774c0 and R7S9210
   - renesas_sdhi: Whitelist R8A77990 SDHI
   - renesas_sdhi: Fixup eMMC HS400 compatibility issues for H3 and M3-W
   - rtsx_usb_sdmmc: Re-work card detection/removal support
   - rtsx_usb_sdmmc: Re-work runtime PM support
   - sdhci: Fix timeout loops for some variant drivers
   - sdhci: Improve support for error handling due to failing commands
   - sdhci-acpi/pci: Disable LED control for Intel BYT-based controllers
   - sdhci_am654: Add new SDHCI variant driver to support TI's AM654 SOCs
   - sdhci-of-esdhc: Add support for eMMC HS400 mode
   - sdhci-omap: Fixup reset support
   - sdhci-omap: Workaround errata regarding SDR104/HS200 tuning failures
   - sdhci-msm: Fixup sporadic write transfers issues for SDR104/HS200
   - sdhci-msm: Fixup dynamical clock gating issues
   - various: Complete converting all hosts into using slot GPIO descriptors

  Other:
   - Move GPIO mmc platform data for mips/sh/arm to GPIO descriptors
   - Add new Alcor Micro cardreader PCI driver
   - Support runtime power management for memstick rtsx_usb_ms driver
   - Use USB remote wakeups for card detection for rtsx_usb misc driver"

* tag 'mmc-v4.21' of git://git.kernel.org/pub/scm/linux/kernel/git/ulfh/mmc: (99 commits)
  mmc: mediatek: Add MMC_CAP_SDIO_IRQ support
  mmc: renesas_sdhi_internal_dmac: Whitelist r8a774c0
  dt-bindings: mmc: renesas_sdhi: Add r8a774c0 support
  mmc: core: Cleanup BKOPS support
  mmc: core: Drop redundant check in mmc_send_hpi_cmd()
  mmc: sdhci-omap: Workaround errata regarding SDR104/HS200 tuning failures (i929)
  dt-bindings: sdhci-omap: Add note for cpu_thermal
  mmc: sdhci-acpi: Disable LED control for Intel BYT-based controllers
  mmc: sdhci-pci: Disable LED control for Intel BYT-based controllers
  mmc: sdhci: Add quirk to disable LED control
  mmc: mmci: add variant property to set command stop bit
  misc: alcor_pci: fix spelling mistake "invailid" -> "invalid"
  mmc: meson-gx: add signal resampling
  mmc: meson-gx: align default phase on soc vendor tree
  mmc: meson-gx: remove useless lock
  mmc: meson-gx: make sure the descriptor is stopped on errors
  mmc: sdhci_am654: Add Initial Support for AM654 SDHCI driver
  dt-bindings: mmc: sdhci-of-arasan: Add deprecated message for AM65
  dt-bindings: mmc: sdhci-am654: Document bindings for the host controllers on TI's AM654 SOCs
  mmc: sdhci-msm: avoid unused function warning
  ...

19 months agoMerge tag 'libnvdimm-for-4.21' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdim...
Linus Torvalds [Fri, 28 Dec 2018 23:05:13 +0000 (15:05 -0800)]
Merge tag 'libnvdimm-for-4.21' of git://git./linux/kernel/git/nvdimm/nvdimm

Pull libnvdimm updates from Dan Williams:
 "The vast bulk of this update is the new support for the security
  capabilities of some nvdimms.

  The userspace tooling for this capability is still a work in progress,
  but the changes survive the existing libnvdimm unit tests. The changes
  also pass manual checkout on hardware and the new nfit_test emulation
  of the security capability.

  The touches of the security/keys/ files have received the necessary
  acks from Mimi and David. Those changes were necessary to allow for a
  new generic encrypted-key type, and allow the nvdimm sub-system to
  lookup key material referenced by the libnvdimm-sysfs interface.

  Summary:

   - Add support for the security features of nvdimm devices that
     implement a security model similar to ATA hard drive security. The
     security model supports locking access to the media at
     device-power-loss, to be unlocked with a passphrase, and
     secure-erase (crypto-scramble).

     Unlike the ATA security case where the kernel expects device
     security to be managed in a pre-OS environment, the libnvdimm
     security implementation allows key provisioning and key-operations
     at OS runtime. Keys are managed with the kernel's encrypted-keys
     facility to provide data-at-rest security for the libnvdimm key
     material. The usage model mirrors fscrypt key management, but is
     driven via libnvdimm sysfs.

   - Miscellaneous updates for api usage and comment fixes"

* tag 'libnvdimm-for-4.21' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm: (21 commits)
  libnvdimm/security: Quiet security operations
  libnvdimm/security: Add documentation for nvdimm security support
  tools/testing/nvdimm: add Intel DSM 1.8 support for nfit_test
  tools/testing/nvdimm: Add overwrite support for nfit_test
  tools/testing/nvdimm: Add test support for Intel nvdimm security DSMs
  acpi/nfit, libnvdimm/security: add Intel DSM 1.8 master passphrase support
  acpi/nfit, libnvdimm/security: Add security DSM overwrite support
  acpi/nfit, libnvdimm: Add support for issue secure erase DSM to Intel nvdimm
  acpi/nfit, libnvdimm: Add enable/update passphrase support for Intel nvdimms
  acpi/nfit, libnvdimm: Add disable passphrase support to Intel nvdimm.
  acpi/nfit, libnvdimm: Add unlock of nvdimm support for Intel DIMMs
  acpi/nfit, libnvdimm: Add freeze security support to Intel nvdimm
  acpi/nfit, libnvdimm: Introduce nvdimm_security_ops
  keys-encrypted: add nvdimm key format type to encrypted keys
  keys: Export lookup_user_key to external users
  acpi/nfit, libnvdimm: Store dimm id as a member to struct nvdimm
  libnvdimm, namespace: Replace kmemdup() with kstrndup()
  libnvdimm, label: Switch to bitmap_zalloc()
  ACPI/nfit: Adjust annotation for why return 0 if fail to find NFIT at start
  libnvdimm, bus: Check id immediately following ida_simple_get
  ...

19 months agoMerge tag 'for-4.21/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git...
Linus Torvalds [Fri, 28 Dec 2018 23:02:26 +0000 (15:02 -0800)]
Merge tag 'for-4.21/dm-changes' of git://git./linux/kernel/git/device-mapper/linux-dm

Pull device mapper updates from Mike Snitzer:

 - Eliminate a couple indirect calls from bio-based DM core.

 - Fix DM to allow reads that exceed readahead limits by setting
   io_pages in the backing_dev_info.

 - A couple code cleanups in request-based DM.

 - Fix various DM targets to check for device sector overflow if
   CONFIG_LBDAF is not set.

 - Use u64 instead of sector_t to store iv_offset in DM crypt; sector_t
   isn't large enough on 32bit when CONFIG_LBDAF is not set.

 - Performance fixes to DM's kcopyd and the snapshot target focused on
   limiting memory use and workqueue stalls.

 - Fix typos in the integrity and writecache targets.

 - Log which algorithm is used for dm-crypt's encryption and
   dm-integrity's hashing.

 - Fix false -EBUSY errors in DM raid target's handling of check/repair
   messages.

 - Fix DM flakey target's corrupt_bio_byte feature to reliably corrupt
   the Nth byte in a bio's payload.

* tag 'for-4.21/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm: do not allow readahead to limit IO size
  dm raid: fix false -EBUSY when handling check/repair message
  dm rq: cleanup leftover code from recently removed q->mq_ops branching
  dm verity: log the hash algorithm implementation
  dm crypt: log the encryption algorithm implementation
  dm integrity: fix spelling mistake in workqueue name
  dm flakey: Properly corrupt multi-page bios.
  dm: Check for device sector overflow if CONFIG_LBDAF is not set
  dm crypt: use u64 instead of sector_t to store iv_offset
  dm kcopyd: Fix bug causing workqueue stalls
  dm snapshot: Fix excessive memory usage and workqueue stalls
  dm bufio: update comment in dm-bufio.c
  dm writecache: fix typo in error msg for creating writecache_flush_thread
  dm: remove indirect calls from __send_changing_extent_only()
  dm mpath: only flush workqueue when needed
  dm rq: remove unused arguments from rq_completed()
  dm: avoid indirect call in __dm_make_request

19 months agoMerge tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma
Linus Torvalds [Fri, 28 Dec 2018 22:57:10 +0000 (14:57 -0800)]
Merge tag 'for-linus' of git://git./linux/kernel/git/rdma/rdma

Pull rdma updates from Jason Gunthorpe:
 "This has been a fairly typical cycle, with the usual sorts of driver
  updates. Several series continue to come through which improve and
  modernize various parts of the core code, and we finally are starting
  to get the uAPI command interface cleaned up.

   - Various driver fixes for bnxt_re, cxgb3/4, hfi1, hns, i40iw, mlx4,
     mlx5, qib, rxe, usnic

   - Rework the entire syscall flow for uverbs to be able to run over
     ioctl(). Finally getting past the historic bad choice to use
     write() for command execution

   - More functional coverage with the mlx5 'devx' user API

   - Start of the HFI1 series for 'TID RDMA'

   - SRQ support in the hns driver

   - Support for new IBTA defined 2x lane widths

   - A big series to consolidate all the driver function pointers into a
     big struct and have drivers provide a 'static const' version of the
     struct instead of open coding initialization

   - New 'advise_mr' uAPI to control device caching/loading of page
     tables

   - Support for inline data in SRPT

   - Modernize how umad uses the driver core and creates cdev's and
     sysfs files

   - First steps toward removing 'uobject' from the view of the drivers"

* tag 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma: (193 commits)
  RDMA/srpt: Use kmem_cache_free() instead of kfree()
  RDMA/mlx5: Signedness bug in UVERBS_HANDLER()
  IB/uverbs: Signedness bug in UVERBS_HANDLER()
  IB/mlx5: Allocate the per-port Q counter shared when DEVX is supported
  IB/umad: Start using dev_groups of class
  IB/umad: Use class_groups and let core create class file
  IB/umad: Refactor code to use cdev_device_add()
  IB/umad: Avoid destroying device while it is accessed
  IB/umad: Simplify and avoid dynamic allocation of class
  IB/mlx5: Fix wrong error unwind
  IB/mlx4: Remove set but not used variable 'pd'
  RDMA/iwcm: Don't copy past the end of dev_name() string
  IB/mlx5: Fix long EEH recover time with NVMe offloads
  IB/mlx5: Simplify netdev unbinding
  IB/core: Move query port to ioctl
  RDMA/nldev: Expose port_cap_flags2
  IB/core: uverbs copy to struct or zero helper
  IB/rxe: Reuse code which sets port state
  IB/rxe: Make counters thread safe
  IB/mlx5: Use the correct commands for UMEM and UCTX allocation
  ...

19 months agoMerge tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi
Linus Torvalds [Fri, 28 Dec 2018 22:48:06 +0000 (14:48 -0800)]
Merge tag 'scsi-misc' of git://git./linux/kernel/git/jejb/scsi

Pull SCSI updates from James Bottomley:
 "This is mostly update of the usual drivers: smarpqi, lpfc, qedi,
  megaraid_sas, libsas, zfcp, mpt3sas, hisi_sas.

  Additionally, we have a pile of annotation, unused variable and minor
  updates.

  The big API change is the updates for Christoph's DMA rework which
  include removing the DISABLE_CLUSTERING flag.

  And finally there are a couple of target tree updates"

* tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (259 commits)
  scsi: isci: request: mark expected switch fall-through
  scsi: isci: remote_node_context: mark expected switch fall-throughs
  scsi: isci: remote_device: Mark expected switch fall-throughs
  scsi: isci: phy: Mark expected switch fall-through
  scsi: iscsi: Capture iscsi debug messages using tracepoints
  scsi: myrb: Mark expected switch fall-throughs
  scsi: megaraid: fix out-of-bound array accesses
  scsi: mpt3sas: mpt3sas_scsih: Mark expected switch fall-through
  scsi: fcoe: remove set but not used variable 'port'
  scsi: smartpqi: call pqi_free_interrupts() in pqi_shutdown()
  scsi: smartpqi: fix build warnings
  scsi: smartpqi: update driver version
  scsi: smartpqi: add ofa support
  scsi: smartpqi: increase fw status register read timeout
  scsi: smartpqi: bump driver version
  scsi: smartpqi: add smp_utils support
  scsi: smartpqi: correct lun reset issues
  scsi: smartpqi: correct volume status
  scsi: smartpqi: do not offline disks for transient did no connect conditions
  scsi: smartpqi: allow for larger raid maps
  ...

19 months agoMerge tag 'dma-mapping-4.21' of git://git.infradead.org/users/hch/dma-mapping
Linus Torvalds [Fri, 28 Dec 2018 22:12:21 +0000 (14:12 -0800)]
Merge tag 'dma-mapping-4.21' of git://git.infradead.org/users/hch/dma-mapping

Pull DMA mapping updates from Christoph Hellwig:
 "A huge update this time, but a lot of that is just consolidating or
  removing code:

   - provide a common DMA_MAPPING_ERROR definition and avoid indirect
     calls for dma_map_* error checking

   - use direct calls for the DMA direct mapping case, avoiding huge
     retpoline overhead for high performance workloads

   - merge the swiotlb dma_map_ops into dma-direct

   - provide a generic remapping DMA consistent allocator for
     architectures that have devices that perform DMA that is not cache
     coherent. Based on the existing arm64 implementation and also used
     for csky now.

   - improve the dma-debug infrastructure, including dynamic allocation
     of entries (Robin Murphy)

   - default to providing chaining scatterlist everywhere, with opt-outs
     for the few architectures (alpha, parisc, most arm32 variants) that
     can't cope with it

   - misc sparc32 dma-related cleanups

   - remove the dma_mark_clean arch hook used by swiotlb on ia64 and
     replace it with the generic noncoherent infrastructure

   - fix the return type of dma_set_max_seg_size (Niklas Söderlund)

   - move the dummy dma ops for not DMA capable devices from arm64 to
     common code (Robin Murphy)

   - ensure dma_alloc_coherent returns zeroed memory to avoid kernel
     data leaks through userspace. We already did this for most common
     architectures, but this ensures we do it everywhere.
     dma_zalloc_coherent has been deprecated and can hopefully be
     removed after -rc1 with a coccinelle script"

* tag 'dma-mapping-4.21' of git://git.infradead.org/users/hch/dma-mapping: (73 commits)
  dma-mapping: fix inverted logic in dma_supported
  dma-mapping: deprecate dma_zalloc_coherent
  dma-mapping: zero memory returned from dma_alloc_*
  sparc/iommu: fix ->map_sg return value
  sparc/io-unit: fix ->map_sg return value
  arm64: default to the direct mapping in get_arch_dma_ops
  PCI: Remove unused attr variable in pci_dma_configure
  ia64: only select ARCH_HAS_DMA_COHERENT_TO_PFN if swiotlb is enabled
  dma-mapping: bypass indirect calls for dma-direct
  vmd: use the proper dma_* APIs instead of direct methods calls
  dma-direct: merge swiotlb_dma_ops into the dma_direct code
  dma-direct: use dma_direct_map_page to implement dma_direct_map_sg
  dma-direct: improve addressability error reporting
  swiotlb: remove dma_mark_clean
  swiotlb: remove SWIOTLB_MAP_ERROR
  ACPI / scan: Refactor _CCA enforcement
  dma-mapping: factor out dummy DMA ops
  dma-mapping: always build the direct mapping code
  dma-mapping: move dma_cache_sync out of line
  dma-mapping: move various slow path functions out of line
  ...

19 months agoMerge tag 'for-4.21/libata-20181221' of git://git.kernel.dk/linux-block
Linus Torvalds [Fri, 28 Dec 2018 22:06:43 +0000 (14:06 -0800)]
Merge tag 'for-4.21/libata-20181221' of git://git.kernel.dk/linux-block

Pull libata updates from Jens Axboe:
 "Here are the libata changes for this merge window. Nothing major in
  here. This contains:

   - GPIO descriptor conversions (Linus Walleij)

   - rcar deferred probing fix (Sergei Shtylyov)"

* tag 'for-4.21/libata-20181221' of git://git.kernel.dk/linux-block:
  sata_rcar: fix deferred probing
  ata: palmld: Introduce state container
  ata: palmld: Convert to GPIO descriptors
  ata: rb532_cf: Convert to use GPIO descriptors
  ata: sata_highbank: Convert to use GPIO descriptors
  ata: pxa: Drop <linux/gpio.h> include

19 months agoMerge tag 'for-4.21/aio-20181221' of git://git.kernel.dk/linux-block
Linus Torvalds [Fri, 28 Dec 2018 21:57:59 +0000 (13:57 -0800)]
Merge tag 'for-4.21/aio-20181221' of git://git.kernel.dk/linux-block

Pull aio updates from Jens Axboe:
 "Flushing out pre-patches for the buffered/polled aio series. Some
  fixes in here, but also optimizations"

* tag 'for-4.21/aio-20181221' of git://git.kernel.dk/linux-block:
  aio: abstract out io_event filler helper
  aio: split out iocb copy from io_submit_one()
  aio: use iocb_put() instead of open coding it
  aio: only use blk plugs for > 2 depth submissions
  aio: don't zero entire aio_kiocb aio_get_req()
  aio: separate out ring reservation from req allocation
  aio: use assigned completion handler

19 months agoMerge tag 'for-4.21/block-20181221' of git://git.kernel.dk/linux-block
Linus Torvalds [Fri, 28 Dec 2018 21:19:59 +0000 (13:19 -0800)]
Merge tag 'for-4.21/block-20181221' of git://git.kernel.dk/linux-block

Pull block updates from Jens Axboe:
 "This is the main pull request for block/storage for 4.21.

  Larger than usual, it was a busy round with lots of goodies queued up.
  Most notable is the removal of the old IO stack, which has been a long
  time coming. No new features for a while, everything coming in this
  week has all been fixes for things that were previously merged.

  This contains:

   - Use atomic counters instead of semaphores for mtip32xx (Arnd)

   - Cleanup of the mtip32xx request setup (Christoph)

   - Fix for circular locking dependency in loop (Jan, Tetsuo)

   - bcache (Coly, Guoju, Shenghui)
      * Optimizations for writeback caching
      * Various fixes and improvements

   - nvme (Chaitanya, Christoph, Sagi, Jay, me, Keith)
      * host and target support for NVMe over TCP
      * Error log page support
      * Support for separate read/write/poll queues
      * Much improved polling
      * discard OOM fallback
      * Tracepoint improvements

   - lightnvm (Hans, Hua, Igor, Matias, Javier)
      * Igor added packed metadata to pblk. Now drives without metadata
        per LBA can be used as well.
      * Fix from Geert on uninitialized value on chunk metadata reads.
      * Fixes from Hans and Javier to pblk recovery and write path.
      * Fix from Hua Su to fix a race condition in the pblk recovery
        code.
      * Scan optimization added to pblk recovery from Zhoujie.
      * Small geometry cleanup from me.

   - Conversion of the last few drivers that used the legacy path to
     blk-mq (me)

   - Removal of legacy IO path in SCSI (me, Christoph)

   - Removal of legacy IO stack and schedulers (me)

   - Support for much better polling, now without interrupts at all.
     blk-mq adds support for multiple queue maps, which enables us to
     have a map per type. This in turn enables nvme to have separate
     completion queues for polling, which can then be interrupt-less.
     Also means we're ready for async polled IO, which is hopefully
     coming in the next release.

   - Killing of (now) unused block exports (Christoph)

   - Unification of the blk-rq-qos and blk-wbt wait handling (Josef)

   - Support for zoned testing with null_blk (Masato)

   - sx8 conversion to per-host tag sets (Christoph)

   - IO priority improvements (Damien)

   - mq-deadline zoned fix (Damien)

   - Ref count blkcg series (Dennis)

   - Lots of blk-mq improvements and speedups (me)

   - sbitmap scalability improvements (me)

   - Make core inflight IO accounting per-cpu (Mikulas)

   - Export timeout setting in sysfs (Weiping)

   - Cleanup the direct issue path (Jianchao)

   - Export blk-wbt internals in block debugfs for easier debugging
     (Ming)

   - Lots of other fixes and improvements"

* tag 'for-4.21/block-20181221' of git://git.kernel.dk/linux-block: (364 commits)
  kyber: use sbitmap add_wait_queue/list_del wait helpers
  sbitmap: add helpers for add/del wait queue handling
  block: save irq state in blkg_lookup_create()
  dm: don't reuse bio for flushes
  nvme-pci: trace SQ status on completions
  nvme-rdma: implement polling queue map
  nvme-fabrics: allow user to pass in nr_poll_queues
  nvme-fabrics: allow nvmf_connect_io_queue to poll
  nvme-core: optionally poll sync commands
  block: make request_to_qc_t public
  nvme-tcp: fix spelling mistake "attepmpt" -> "attempt"
  nvme-tcp: fix endianess annotations
  nvmet-tcp: fix endianess annotations
  nvme-pci: refactor nvme_poll_irqdisable to make sparse happy
  nvme-pci: only set nr_maps to 2 if poll queues are supported
  nvmet: use a macro for default error location
  nvmet: fix comparison of a u16 with -1
  blk-mq: enable IO poll if .nr_queues of type poll > 0
  blk-mq: change blk_mq_queue_busy() to blk_mq_queue_inflight()
  blk-mq: skip zero-queue maps in blk_mq_map_swqueue
  ...

19 months agoMerge tag 'y2038-for-4.21' of ssh://gitolite.kernel.org:/pub/scm/linux/kernel/git...
Linus Torvalds [Fri, 28 Dec 2018 20:45:04 +0000 (12:45 -0800)]
Merge tag 'y2038-for-4.21' of ssh://gitolite./linux/kernel/git/arnd/playground

Pull y2038 updates from Arnd Bergmann:
 "More syscalls and cleanups

  This concludes the main part of the system call rework for 64-bit
  time_t, which has spread over most of year 2018, the last six system
  calls being

    - ppoll
    - pselect6
    - io_pgetevents
    - recvmmsg
    - futex
    - rt_sigtimedwait

  As before, nothing changes for 64-bit architectures, while 32-bit
  architectures gain another entry point that differs only in the layout
  of the timespec structure. Hopefully in the next release we can wire
  up all 22 of those system calls on all 32-bit architectures, which
  gives us a baseline version for glibc to start using them.

  This does not include the clock_adjtime, getrusage/waitid, and
  getitimer/setitimer system calls. I still plan to have new versions of
  those as well, but they are not required for correct operation of the
  C library since they can be emulated using the old 32-bit time_t based
  system calls.

  Aside from the system calls, there are also a few cleanups here,
  removing old kernel internal interfaces that have become unused after
  all references got removed. The arch/sh cleanups are part of this,
  there were posted several times over the past year without a reaction
  from the maintainers, while the corresponding changes made it into all
  other architectures"

* tag 'y2038-for-4.21' of ssh://gitolite.kernel.org:/pub/scm/linux/kernel/git/arnd/playground:
  timekeeping: remove obsolete time accessors
  vfs: replace current_kernel_time64 with ktime equivalent
  timekeeping: remove timespec_add/timespec_del
  timekeeping: remove unused {read,update}_persistent_clock
  sh: remove board_time_init() callback
  sh: remove unused rtc_sh_get/set_time infrastructure
  sh: sh03: rtc: push down rtc class ops into driver
  sh: dreamcast: rtc: push down rtc class ops into driver
  y2038: signal: Add compat_sys_rt_sigtimedwait_time64
  y2038: signal: Add sys_rt_sigtimedwait_time32
  y2038: socket: Add compat_sys_recvmmsg_time64
  y2038: futex: Add support for __kernel_timespec
  y2038: futex: Move compat implementation into futex.c
  io_pgetevents: use __kernel_timespec
  pselect6: use __kernel_timespec
  ppoll: use __kernel_timespec
  signal: Add restore_user_sigmask()
  signal: Add set_user_sigmask()

19 months agoFix failure path in alloc_pid()
Matthew Wilcox [Fri, 28 Dec 2018 15:22:26 +0000 (07:22 -0800)]
Fix failure path in alloc_pid()

The failure path removes the allocated PIDs from the wrong namespace.
This could lead to us inadvertently reusing PIDs in the leaf namespace
and leaking PIDs in parent namespaces.

Fixes: 95846ecf9dac ("pid: replace pid bitmap implementation with IDR API")
Cc: <stable@vger.kernel.org>
Signed-off-by: Matthew Wilcox <willy@infradead.org>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agokernel/fork.c: mark 'stack_vm_area' with __maybe_unused
YueHaibing [Fri, 28 Dec 2018 08:40:00 +0000 (00:40 -0800)]
kernel/fork.c: mark 'stack_vm_area' with __maybe_unused

Fixes gcc '-Wunused-but-set-variable' warning when CONFIG_VMAP_STACK is
not set:

kernel/fork.c: In function 'dup_task_struct':
kernel/fork.c:843:20: warning:
 variable 'stack_vm_area' set but not used [-Wunused-but-set-variable]

Link: http://lkml.kernel.org/r/1545965190-2381-1-git-send-email-yuehaibing@huawei.com
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomemcg, oom: notify on oom killer invocation from the charge path
Michal Hocko [Fri, 28 Dec 2018 08:39:57 +0000 (00:39 -0800)]
memcg, oom: notify on oom killer invocation from the charge path

Burt Holzman has noticed that memcg v1 doesn't notify about OOM events via
eventfd anymore.  The reason is that 29ef680ae7c2 ("memcg, oom: move
out_of_memory back to the charge path") has moved the oom handling back to
the charge path.  While doing so the notification was left behind in
mem_cgroup_oom_synchronize.

Fix the issue by replicating the oom hierarchy locking and the
notification.

Link: http://lkml.kernel.org/r/20181224091107.18354-1-mhocko@kernel.org
Fixes: 29ef680ae7c2 ("memcg, oom: move out_of_memory back to the charge path")
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Burt Holzman <burt@fnal.gov>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com
Cc: <stable@vger.kernel.org> [4.19+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm, swap: fix swapoff with KSM pages
Huang Ying [Fri, 28 Dec 2018 08:39:53 +0000 (00:39 -0800)]
mm, swap: fix swapoff with KSM pages

KSM pages may be mapped to the multiple VMAs that cannot be reached from
one anon_vma.  So during swapin, a new copy of the page need to be
generated if a different anon_vma is needed, please refer to comments of
ksm_might_need_to_copy() for details.

During swapoff, unuse_vma() uses anon_vma (if available) to locate VMA and
virtual address mapped to the page, so not all mappings to a swapped out
KSM page could be found.  So in try_to_unuse(), even if the swap count of
a swap entry isn't zero, the page needs to be deleted from swap cache, so
that, in the next round a new page could be allocated and swapin for the
other mappings of the swapped out KSM page.

But this contradicts with the THP swap support.  Where the THP could be
deleted from swap cache only after the swap count of every swap entry in
the huge swap cluster backing the THP has reach 0.  So try_to_unuse() is
changed in commit e07098294adf ("mm, THP, swap: support to reclaim swap
space for THP swapped out") to check that before delete a page from swap
cache, but this has broken KSM swapoff too.

Fortunately, KSM is for the normal pages only, so the original behavior
for KSM pages could be restored easily via checking PageTransCompound().
That is how this patch works.

The bug is introduced by e07098294adf ("mm, THP, swap: support to reclaim
swap space for THP swapped out"), which is merged by v4.14-rc1.  So I
think we should backport the fix to from 4.14 on.  But Hugh thinks it may
be rare for the KSM pages being in the swap device when swapoff, so nobody
reports the bug so far.

Link: http://lkml.kernel.org/r/20181226051522.28442-1-ying.huang@intel.com
Fixes: e07098294adf ("mm, THP, swap: support to reclaim swap space for THP swapped out")
Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Reported-by: Hugh Dickins <hughd@google.com>
Tested-by: Hugh Dickins <hughd@google.com>
Acked-by: Hugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Shaohua Li <shli@kernel.org>
Cc: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agoinclude/linux/gfp.h: fix typo
Kyle Spiers [Fri, 28 Dec 2018 08:39:49 +0000 (00:39 -0800)]
include/linux/gfp.h: fix typo

Fix misspelled "satisfied"

Link: http://lkml.kernel.org/r/20181227232354.64562-1-ksspiers@google.com
Signed-off-by: Kyle Spiers <ksspiers@google.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm/hmm: fix memremap.h, move dev_page_fault_t callback to hmm
Dan Williams [Fri, 28 Dec 2018 08:39:46 +0000 (00:39 -0800)]
mm/hmm: fix memremap.h, move dev_page_fault_t callback to hmm

The kbuild robot reported the following on a development branch that used
memremap.h in a new path:

   In file included from arch/m68k/include/asm/pgtable_mm.h:148:0,
                     from arch/m68k/include/asm/pgtable.h:5,
                     from include/linux/memremap.h:7,
                     from drivers//dax/bus.c:3:
    arch/m68k/include/asm/motorola_pgtable.h: In function 'pgd_offset':
 >> arch/m68k/include/asm/motorola_pgtable.h:199:11: error: dereferencing pointer to incomplete type 'const struct mm_struct'
      return mm->pgd + pgd_index(address);
               ^~

The ->page_fault() callback is specific to HMM.  Move it to 'struct
hmm_devmem' where the unusual asm/pgtable.h dependency can be contained in
include/linux/hmm.h.  Longer term refactoring this dependency out of HMM
is recommended, but in the meantime memremap.h remains generic.

Link: http://lkml.kernel.org/r/154534090899.3120190.6652620807617715272.stgit@dwillia2-desk3.amr.corp.intel.com
Fixes: 5042db43cc26 ("mm/ZONE_DEVICE: new type of ZONE_DEVICE memory...")
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: "Jérôme Glisse" <jglisse@redhat.com>
Cc: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agohugetlbfs: Use i_mmap_rwsem to fix page fault/truncate race
Mike Kravetz [Fri, 28 Dec 2018 08:39:42 +0000 (00:39 -0800)]
hugetlbfs: Use i_mmap_rwsem to fix page fault/truncate race

hugetlbfs page faults can race with truncate and hole punch operations.
Current code in the page fault path attempts to handle this by 'backing
out' operations if we encounter the race.  One obvious omission in the
current code is removing a page newly added to the page cache.  This is
pretty straight forward to address, but there is a more subtle and
difficult issue of backing out hugetlb reservations.  To handle this
correctly, the 'reservation state' before page allocation needs to be
noted so that it can be properly backed out.  There are four distinct
possibilities for reservation state: shared/reserved, shared/no-resv,
private/reserved and private/no-resv.  Backing out a reservation may
require memory allocation which could fail so that needs to be taken into
account as well.

Instead of writing the required complicated code for this rare occurrence,
just eliminate the race.  i_mmap_rwsem is now held in read mode for the
duration of page fault processing.  Hold i_mmap_rwsem longer in truncation
and hold punch code to cover the call to remove_inode_hugepages.

With this modification, code in remove_inode_hugepages checking for races
becomes 'dead' as it can not longer happen.  Remove the dead code and
expand comments to explain reasoning.  Similarly, checks for races with
truncation in the page fault path can be simplified and removed.

[mike.kravetz@oracle.com: incorporat suggestions from Kirill]
Link: http://lkml.kernel.org/r/20181222223013.22193-3-mike.kravetz@oracle.com
Link: http://lkml.kernel.org/r/20181218223557.5202-3-mike.kravetz@oracle.com
Fixes: ebed4bfc8da8 ("hugetlb: fix absurd HugePages_Rsvd")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Prakash Sangappa <prakash.sangappa@oracle.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agohugetlbfs: use i_mmap_rwsem for more pmd sharing synchronization
Mike Kravetz [Fri, 28 Dec 2018 08:39:38 +0000 (00:39 -0800)]
hugetlbfs: use i_mmap_rwsem for more pmd sharing synchronization

While looking at BUGs associated with invalid huge page map counts, it was
discovered and observed that a huge pte pointer could become 'invalid' and
point to another task's page table.  Consider the following:

A task takes a page fault on a shared hugetlbfs file and calls
huge_pte_alloc to get a ptep.  Suppose the returned ptep points to a
shared pmd.

Now, another task truncates the hugetlbfs file.  As part of truncation, it
unmaps everyone who has the file mapped.  If the range being truncated is
covered by a shared pmd, huge_pmd_unshare will be called.  For all but the
last user of the shared pmd, huge_pmd_unshare will clear the pud pointing
to the pmd.  If the task in the middle of the page fault is not the last
user, the ptep returned by huge_pte_alloc now points to another task's
page table or worse.  This leads to bad things such as incorrect page
map/reference counts or invalid memory references.

To fix, expand the use of i_mmap_rwsem as follows:

- i_mmap_rwsem is held in read mode whenever huge_pmd_share is called.
  huge_pmd_share is only called via huge_pte_alloc, so callers of
  huge_pte_alloc take i_mmap_rwsem before calling.  In addition, callers
  of huge_pte_alloc continue to hold the semaphore until finished with the
  ptep.

- i_mmap_rwsem is held in write mode whenever huge_pmd_unshare is
  called.

[mike.kravetz@oracle.com: add explicit check for mapping != null]
Link: http://lkml.kernel.org/r/20181218223557.5202-2-mike.kravetz@oracle.com
Fixes: 39dde65c9940 ("shared page table for hugetlb page")
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Hugh Dickins <hughd@google.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: "Aneesh Kumar K . V" <aneesh.kumar@linux.vnet.ibm.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Prakash Sangappa <prakash.sangappa@oracle.com>
Cc: Colin Ian King <colin.king@canonical.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomemory_hotplug: add missing newlines to debugging output
Michal Hocko [Fri, 28 Dec 2018 08:39:34 +0000 (00:39 -0800)]
memory_hotplug: add missing newlines to debugging output

pages_correctly_probed is missing new lines which means that the line is
not printed rightaway but it rather waits for additional printks.

Add \n to all three messages in pages_correctly_probed.

Link: http://lkml.kernel.org/r/20181218162307.10518-1-mhocko@kernel.org
Fixes: b77eab7079d9 ("mm/memory_hotplug: optimize probe routine")
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm: remove __hugepage_set_anon_rmap()
Kirill Tkhai [Fri, 28 Dec 2018 08:39:31 +0000 (00:39 -0800)]
mm: remove __hugepage_set_anon_rmap()

This function is identical to __page_set_anon_rmap() since the time, when
it was introduced (8 years ago).  The patch removes the function, and
makes its users to use __page_set_anon_rmap() instead.

Link: http://lkml.kernel.org/r/154504875359.30235.6237926369392564851.stgit@localhost.localdomain
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agoinclude/linux/vmstat.h: remove unused page state adjustment macro
Wei Yang [Fri, 28 Dec 2018 08:39:27 +0000 (00:39 -0800)]
include/linux/vmstat.h: remove unused page state adjustment macro

These four macro are not used anymore.

Just remove them.

Link: http://lkml.kernel.org/r/20181214063211.2290-1-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm/page_alloc.c: allow error injection
Benjamin Poirier [Fri, 28 Dec 2018 08:39:23 +0000 (00:39 -0800)]
mm/page_alloc.c: allow error injection

Model call chain after should_failslab().  Likewise, we can now use a
kprobe to override the return value of should_fail_alloc_page() and inject
allocation failures into alloc_page*().

This will allow injecting allocation failures using the BCC tools even
without building kernel with CONFIG_FAIL_PAGE_ALLOC and booting it with a
fail_page_alloc= parameter, which incurs some overhead even when failures
are not being injected.  On the other hand, this patch adds an
unconditional call to should_fail_alloc_page() from page allocation
hotpath.  That overhead should be rather negligible with
CONFIG_FAIL_PAGE_ALLOC=n when there's no kprobe attached, though.

[vbabka@suse.cz: changelog addition]
Link: http://lkml.kernel.org/r/20181214074330.18917-1-bpoirier@suse.com
Signed-off-by: Benjamin Poirier <bpoirier@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Pavel Tatashin <pavel.tatashin@microsoft.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm: migrate: drop unused argument of migrate_page_move_mapping()
Jan Kara [Fri, 28 Dec 2018 08:39:20 +0000 (00:39 -0800)]
mm: migrate: drop unused argument of migrate_page_move_mapping()

All callers of migrate_page_move_mapping() now pass NULL for 'head'
argument.  Drop it.

Link: http://lkml.kernel.org/r/20181211172143.7358-7-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agoblkdev: avoid migration stalls for blkdev pages
Jan Kara [Fri, 28 Dec 2018 08:39:16 +0000 (00:39 -0800)]
blkdev: avoid migration stalls for blkdev pages

Currently, block device pages don't provide a ->migratepage callback and
thus fallback_migrate_page() is used for them.  This handler cannot deal
with dirty pages in async mode and also with the case a buffer head is in
the LRU buffer head cache (as it has elevated b_count).  Thus such page
can block memory offlining.

Fix the problem by using buffer_migrate_page_norefs() for migrating block
device pages.  That function takes care of dropping bh LRU in case
migration would fail due to elevated buffer refcount to avoid stalls and
can also migrate dirty pages without writing them.

Link: http://lkml.kernel.org/r/20181211172143.7358-6-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm: migrate: provide buffer_migrate_page_norefs()
Jan Kara [Fri, 28 Dec 2018 08:39:12 +0000 (00:39 -0800)]
mm: migrate: provide buffer_migrate_page_norefs()

Provide a variant of buffer_migrate_page() that also checks whether there
are no unexpected references to buffer heads.  This function will then be
safe to use for block device pages.

[akpm@linux-foundation.org: remove EXPORT_SYMBOL(buffer_migrate_page_norefs)]
Link: http://lkml.kernel.org/r/20181211172143.7358-5-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm: migrate: move migrate_page_lock_buffers()
Jan Kara [Fri, 28 Dec 2018 08:39:09 +0000 (00:39 -0800)]
mm: migrate: move migrate_page_lock_buffers()

buffer_migrate_page() is the only caller of migrate_page_lock_buffers()
move it close to it and also drop the now unused stub for !CONFIG_BLOCK.

Link: http://lkml.kernel.org/r/20181211172143.7358-4-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm: migrate: lock buffers before migrate_page_move_mapping()
Jan Kara [Fri, 28 Dec 2018 08:39:05 +0000 (00:39 -0800)]
mm: migrate: lock buffers before migrate_page_move_mapping()

Lock buffers before calling into migrate_page_move_mapping() so that that
function doesn't have to know about buffers (which is somewhat unexpected
anyway) and all the buffer head logic is in buffer_migrate_page().

Link: http://lkml.kernel.org/r/20181211172143.7358-3-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm: migration: factor out code to compute expected number of page references
Jan Kara [Fri, 28 Dec 2018 08:39:01 +0000 (00:39 -0800)]
mm: migration: factor out code to compute expected number of page references

Patch series "mm: migrate: Fix page migration stalls for blkdev pages".

This patchset deals with page migration stalls that were reported by our
customer due to a block device page that had a bufferhead that was in the
bh LRU cache.

The patchset modifies the page migration code so that bufferheads are
completely handled inside buffer_migrate_page() and then provides a new
migration helper for pages with buffer heads that is safe to use even for
block device pages and that also deals with bh lrus.

This patch (of 6):

Factor out function to compute number of expected page references in
migrate_page_move_mapping().  Note that we move hpage_nr_pages() and
page_has_private() checks from under xas_lock_irq() however this is safe
since we hold page lock.

[jack@suse.cz: fix expected_page_refs()]
Link: http://lkml.kernel.org/r/20181217131710.GB8611@quack2.suse.cz
Link: http://lkml.kernel.org/r/20181211172143.7358-2-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm, page_alloc: enable pcpu_drain with zone capability
Wei Yang [Fri, 28 Dec 2018 08:38:58 +0000 (00:38 -0800)]
mm, page_alloc: enable pcpu_drain with zone capability

drain_all_pages is documented to drain per-cpu pages for a given zone (if
non-NULL).  The current implementation doesn't match the description
though.  It will drain all pcp pages for all zones that happen to have
cached pages on the same cpu as the given zone.  This will lead to
premature pcp cache draining for zones that are not of any interest to the
caller - e.g.  compaction, hwpoison or memory offline.

This forces the page allocator to take locks and potential lock contention
as a result.

There is no real reason for this sub-optimal implementation.  Replace
per-cpu work item with a dedicated structure which contains a pointer to
the zone and pass it over to the worker.  This will get the zone
information all the way down to the worker function and do the right job.

[akpm@linux-foundation.org: avoid 80-col tricks]
[mhocko@suse.com: refactor the whole changelog]
Link: http://lkml.kernel.org/r/20181212142550.61686-1-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agokmemleak: add config to select auto scan
Sri Krishna chowdary [Fri, 28 Dec 2018 08:38:54 +0000 (00:38 -0800)]
kmemleak: add config to select auto scan

Kmemleak scan can be cpu intensive and can stall user tasks at times.  To
prevent this, add config DEBUG_KMEMLEAK_AUTO_SCAN to enable/disable auto
scan on boot up.  Also protect first_run with DEBUG_KMEMLEAK_AUTO_SCAN as
this is meant for only first automatic scan.

Link: http://lkml.kernel.org/r/1540231723-7087-1-git-send-email-prpatel@nvidia.com
Signed-off-by: Sri Krishna chowdary <schowdary@nvidia.com>
Signed-off-by: Sachin Nikam <snikam@nvidia.com>
Signed-off-by: Prateek <prpatel@nvidia.com>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm/page_alloc.c: don't call kasan_free_pages() at deferred mem init
Waiman Long [Fri, 28 Dec 2018 08:38:51 +0000 (00:38 -0800)]
mm/page_alloc.c: don't call kasan_free_pages() at deferred mem init

When CONFIG_KASAN is enabled on large memory SMP systems, the deferrred
pages initialization can take a long time.  Below were the reported init
times on a 8-socket 96-core 4TB IvyBridge system.

  1) Non-debug kernel without CONFIG_KASAN
     [    8.764222] node 1 initialised, 132086516 pages in 7027ms

  2) Debug kernel with CONFIG_KASAN
     [  146.288115] node 1 initialised, 132075466 pages in 143052ms

So the page init time in a debug kernel was 20X of the non-debug kernel.
The long init time can be problematic as the page initialization is done
with interrupt disabled.  In this particular case, it caused the
appearance of following warning messages as well as NMI backtraces of all
the cores that were doing the initialization.

[   68.240049] rcu: INFO: rcu_sched detected stalls on CPUs/tasks:
[   68.241000] rcu:  25-...0: (100 ticks this GP) idle=b72/1/0x4000000000000000 softirq=915/915 fqs=16252
[   68.241000] rcu:  44-...0: (95 ticks this GP) idle=49a/1/0x4000000000000000 softirq=788/788 fqs=16253
[   68.241000] rcu:  54-...0: (104 ticks this GP) idle=03a/1/0x4000000000000000 softirq=721/825 fqs=16253
[   68.241000] rcu:  60-...0: (103 ticks this GP) idle=cbe/1/0x4000000000000000 softirq=637/740 fqs=16253
[   68.241000] rcu:  72-...0: (105 ticks this GP) idle=786/1/0x4000000000000000 softirq=536/641 fqs=16253
[   68.241000] rcu:  84-...0: (99 ticks this GP) idle=292/1/0x4000000000000000 softirq=537/537 fqs=16253
[   68.241000] rcu:  111-...0: (104 ticks this GP) idle=bde/1/0x4000000000000000 softirq=474/476 fqs=16253
[   68.241000] rcu:  (detected by 13, t=65018 jiffies, g=249, q=2)

The long init time was mainly caused by the call to kasan_free_pages() to
poison the newly initialized pages.  On a 4TB system, we are talking about
almost 500GB of memory probably on the same node.

In reality, we may not need to poison the newly initialized pages before
they are ever allocated.  So KASAN poisoning of freed pages before the
completion of deferred memory initialization is now disabled.  Those pages
will be properly poisoned when they are allocated or freed after deferred
pages initialization is done.

With this change, the new page initialization time became:

[   21.948010] node 1 initialised, 132075466 pages in 18702ms

This was still about double the non-debug kernel time, but was much
better than before.

Link: http://lkml.kernel.org/r/1544459388-8736-1-git-send-email-longman@redhat.com
Signed-off-by: Waiman Long <longman@redhat.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Pasha Tatashin <Pavel.Tatashin@microsoft.com>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agouserfaultfd: clear flag if remap event not enabled
Peter Xu [Fri, 28 Dec 2018 08:38:47 +0000 (00:38 -0800)]
userfaultfd: clear flag if remap event not enabled

When the process being tracked does mremap() without
UFFD_FEATURE_EVENT_REMAP on the corresponding tracking uffd file handle,
we should not generate the remap event, and at the same time we should
clear all the uffd flags on the new VMA.  Without this patch, we can still
have the VM_UFFD_MISSING|VM_UFFD_WP flags on the new VMA even the fault
handling process does not even know the existance of the VMA.

Link: http://lkml.kernel.org/r/20181211053409.20317-1-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Cc: Hugh Dickins <hughd@google.com>
Cc: Pavel Emelyanov <xemul@virtuozzo.com>
Cc: Pravin Shedge <pravin.shedge4linux@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm/pageblock: throw compile error if pageblock_bits cannot hold MIGRATE_TYPES
Pingfan Liu [Fri, 28 Dec 2018 08:38:43 +0000 (00:38 -0800)]
mm/pageblock: throw compile error if pageblock_bits cannot hold MIGRATE_TYPES

Currently, NR_PAGEBLOCK_BITS and MIGRATE_TYPES are not associated by code.
If someone adds extra migrate type, then he may forget to enlarge the
NR_PAGEBLOCK_BITS.  Hence it requires some way to fix.

NR_PAGEBLOCK_BITS depends on MIGRATE_TYPES, while these macro spread on
two different .h file with reverse dependency, it is a little hard to
refer to MIGRATE_TYPES in pageblock-flag.h.  This patch tries to remind
such relation in compiling-time.

Link: http://lkml.kernel.org/r/1544508709-11358-1-git-send-email-kernelfans@gmail.com
Signed-off-by: Pingfan Liu <kernelfans@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Pavel Tatashin <pavel.tatashin@microsoft.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agoksm: react on changing "sleep_millisecs" parameter faster
Kirill Tkhai [Fri, 28 Dec 2018 08:38:40 +0000 (00:38 -0800)]
ksm: react on changing "sleep_millisecs" parameter faster

ksm thread unconditionally sleeps in ksm_scan_thread() after each
iteration:

schedule_timeout_interruptible(
msecs_to_jiffies(ksm_thread_sleep_millisecs))

The timeout is configured in /sys/kernel/mm/ksm/sleep_millisecs.

In case of user writes a big value by a mistake, and the thread enters
into schedule_timeout_interruptible(), it's not possible to cancel the
sleep by writing a new smaler value; the thread is just sleeping till
timeout expires.

The patch fixes the problem by waking the thread each time after the value
is updated.

This also may be useful for debug purposes; and also for userspace
daemons, which change sleep_millisecs value in dependence of system load.

Link: http://lkml.kernel.org/r/154454107680.3258.3558002210423531566.stgit@localhost.localdomain
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Acked-by: Cyrill Gorcunov <gorcunov@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm, fault_around: do not take a reference to a locked page
Michal Hocko [Fri, 28 Dec 2018 08:38:36 +0000 (00:38 -0800)]
mm, fault_around: do not take a reference to a locked page

filemap_map_pages takes a speculative reference to each page in the range
before it tries to lock that page.  While this is correct it also can
influence page migration which will bail out when seeing an elevated
reference count.  The faultaround code would bail on seeing a locked page
so we can pro-actively check the PageLocked bit before
page_cache_get_speculative and prevent from pointless reference count
churn.

Link: http://lkml.kernel.org/r/20181211142741.2607-4-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Suggested-by: Jan Kara <jack@suse.cz>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Hugh Dickins <hughd@google.com>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm, memory_hotplug: deobfuscate migration part of offlining
Michal Hocko [Fri, 28 Dec 2018 08:38:32 +0000 (00:38 -0800)]
mm, memory_hotplug: deobfuscate migration part of offlining

Memory migration might fail during offlining and we keep retrying in that
case.  This is currently obfuscated by goto retry loop.  The code is hard
to follow and as a result it is even suboptimal becase each retry round
scans the full range from start_pfn even though we have successfully
scanned/migrated [start_pfn, pfn] range already.  This is all only because
check_pages_isolated failure has to rescan the full range again.

De-obfuscate the migration retry loop by promoting it to a real for loop.
In fact remove the goto altogether by making it a proper double loop
(yeah, gotos are nasty in this specific case).  In the end we will get a
slightly more optimal code which is better readable.

[akpm@linux-foundation.org: reflow comments to 80 cols]
Link: http://lkml.kernel.org/r/20181211142741.2607-3-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: William Kucharski <william.kucharski@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm, memory_hotplug: try to migrate full pfn range
Michal Hocko [Fri, 28 Dec 2018 08:38:29 +0000 (00:38 -0800)]
mm, memory_hotplug: try to migrate full pfn range

Patch series "few memory offlining enhancements".

I have been chasing memory offlining not making progress recently.  On the
way I have noticed few weird decisions in the code.  The migration itself
is restricted without a reasonable justification and the retry loop around
the migration is quite messy.  This is addressed by patch 1 and patch 2.

Patch 3 is targeting on the faultaround code which has been a hot
candidate for the initial issue reported upstream [2] and that I am
debugging internally.  It turned out to be not the main contributor in the
end but I believe we should address it regardless.  See the patch
description for more details.

[1] http://lkml.kernel.org/r/20181120134323.13007-1-mhocko@kernel.org
[2] http://lkml.kernel.org/r/20181114070909.GB2653@MiWiFi-R3L-srv

This patch (of 3):

do_migrate_range has been limiting the number of pages to migrate to 256
for some reason which is not documented.  Even if the limit made some
sense back then when it was introduced it doesn't really serve a good
purpose these days.  If the range contains huge pages then we break out of
the loop too early and go through LRU and pcp caches draining and
scan_movable_pages is quite suboptimal.

The only reason to limit the number of pages I can think of is to reduce
the potential time to react on the fatal signal.  But even then the number
of pages is a questionable metric because even a single page migration
might block in a non-killable state (e.g.  __unmap_and_move).

Remove the limit and offline the full requested range (this is one
memblock worth of pages with the current code).  Should we ever get a
report that offlining takes too long to react on fatal signal then we
should rather fix the core migration to use killable waits and bailout
on a signal.

Link: http://lkml.kernel.org/r/20181211142741.2607-1-mhocko@kernel.org
Link: http://lkml.kernel.org/r/20181211142741.2607-2-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: William Kucharski <william.kucharski@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm, proc: report PR_SET_THP_DISABLE in proc
Michal Hocko [Fri, 28 Dec 2018 08:38:25 +0000 (00:38 -0800)]
mm, proc: report PR_SET_THP_DISABLE in proc

David Rientjes has reported that commit 1860033237d4 ("mm: make
PR_SET_THP_DISABLE immediately active") has changed the way how we
report THPable VMAs to the userspace.  Their monitoring tool is
triggering false alarms on PR_SET_THP_DISABLE tasks because it considers
an insufficient THP usage as a memory fragmentation resp.  memory
pressure issue.

Before the said commit each newly created VMA inherited VM_NOHUGEPAGE
flag and that got exposed to the userspace via /proc/<pid>/smaps file.
This implementation had its downsides as explained in the commit message
but it is true that the userspace doesn't have any means to query for
the process wide THP enabled/disabled status.

PR_SET_THP_DISABLE is a process wide flag so it makes a lot of sense to
export in the process wide context rather than per-vma.  Introduce a new
field to /proc/<pid>/status which export this status.  If
PR_SET_THP_DISABLE is used then it reports false same as when the THP is
not compiled in.  It doesn't consider the global THP status because we
already export that information via sysfs

Link: http://lkml.kernel.org/r/20181211143641.3503-4-mhocko@kernel.org
Fixes: 1860033237d4 ("mm: make PR_SET_THP_DISABLE immediately active")
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Reported-by: David Rientjes <rientjes@google.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Paul Oppenheimer <bepvte@gmail.com>
Cc: William Kucharski <william.kucharski@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm, thp, proc: report THP eligibility for each vma
Michal Hocko [Fri, 28 Dec 2018 08:38:21 +0000 (00:38 -0800)]
mm, thp, proc: report THP eligibility for each vma

Userspace falls short when trying to find out whether a specific memory
range is eligible for THP.  There are usecases that would like to know
that
http://lkml.kernel.org/r/alpine.DEB.2.21.1809251248450.50347@chino.kir.corp.google.com
: This is used to identify heap mappings that should be able to fault thp
: but do not, and they normally point to a low-on-memory or fragmentation
: issue.

The only way to deduce this now is to query for hg resp.  nh flags and
confronting the state with the global setting.  Except that there is also
PR_SET_THP_DISABLE that might change the picture.  So the final logic is
not trivial.  Moreover the eligibility of the vma depends on the type of
VMA as well.  In the past we have supported only anononymous memory VMAs
but things have changed and shmem based vmas are supported as well these
days and the query logic gets even more complicated because the
eligibility depends on the mount option and another global configuration
knob.

Simplify the current state and report the THP eligibility in
/proc/<pid>/smaps for each existing vma.  Reuse
transparent_hugepage_enabled for this purpose.  The original
implementation of this function assumes that the caller knows that the vma
itself is supported for THP so make the core checks into
__transparent_hugepage_enabled and use it for existing callers.
__show_smap just use the new transparent_hugepage_enabled which also
checks the vma support status (please note that this one has to be out of
line due to include dependency issues).

[mhocko@kernel.org: fix oops with NULL ->f_mapping]
Link: http://lkml.kernel.org/r/20181224185106.GC16738@dhcp22.suse.cz
Link: http://lkml.kernel.org/r/20181211143641.3503-3-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Paul Oppenheimer <bepvte@gmail.com>
Cc: William Kucharski <william.kucharski@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm, proc: be more verbose about unstable VMA flags in /proc/<pid>/smaps
Michal Hocko [Fri, 28 Dec 2018 08:38:17 +0000 (00:38 -0800)]
mm, proc: be more verbose about unstable VMA flags in /proc/<pid>/smaps

Patch series "THP eligibility reporting via proc".

This series of three patches aims at making THP eligibility reporting much
more robust and long term sustainable.  The trigger for the change is a
regression report [2] and the long follow up discussion.  In short the
specific application didn't have good API to query whether a particular
mapping can be backed by THP so it has used VMA flags to workaround that.
These flags represent a deep internal state of VMAs and as such they
should be used by userspace with a great deal of caution.

A similar has happened for [3] when users complained that VM_MIXEDMAP is
no longer set on DAX mappings.  Again a lack of a proper API led to an
abuse.

The first patch in the series tries to emphasise that that the semantic of
flags might change and any application consuming those should be really
careful.

The remaining two patches provide a more suitable interface to address [2]
and provide a consistent API to query the THP status both for each VMA and
process wide as well.  [1]

http://lkml.kernel.org/r/20181120103515.25280-1-mhocko@kernel.org [2]
http://lkml.kernel.org/r/http://lkml.kernel.org/r/alpine.DEB.2.21.1809241054050.224429@chino.kir.corp.google.com
[3] http://lkml.kernel.org/r/20181002100531.GC4135@quack2.suse.cz

This patch (of 3):

Even though vma flags exported via /proc/<pid>/smaps are explicitly
documented to be not guaranteed for future compatibility the warning
doesn't go far enough because it doesn't mention semantic changes to those
flags.  And they are important as well because these flags are a deep
implementation internal to the MM code and the semantic might change at
any time.

Let's consider two recent examples:
http://lkml.kernel.org/r/20181002100531.GC4135@quack2.suse.cz
: commit e1fb4a086495 "dax: remove VM_MIXEDMAP for fsdax and device dax" has
: removed VM_MIXEDMAP flag from DAX VMAs. Now our testing shows that in the
: mean time certain customer of ours started poking into /proc/<pid>/smaps
: and looks at VMA flags there and if VM_MIXEDMAP is missing among the VMA
: flags, the application just fails to start complaining that DAX support is
: missing in the kernel.

http://lkml.kernel.org/r/alpine.DEB.2.21.1809241054050.224429@chino.kir.corp.google.com
: Commit 1860033237d4 ("mm: make PR_SET_THP_DISABLE immediately active")
: introduced a regression in that userspace cannot always determine the set
: of vmas where thp is ineligible.
: Userspace relies on the "nh" flag being emitted as part of /proc/pid/smaps
: to determine if a vma is eligible to be backed by hugepages.
: Previous to this commit, prctl(PR_SET_THP_DISABLE, 1) would cause thp to
: be disabled and emit "nh" as a flag for the corresponding vmas as part of
: /proc/pid/smaps.  After the commit, thp is disabled by means of an mm
: flag and "nh" is not emitted.
: This causes smaps parsing libraries to assume a vma is eligible for thp
: and ends up puzzling the user on why its memory is not backed by thp.

In both cases userspace was relying on a semantic of a specific VMA flag.
The primary reason why that happened is a lack of a proper interface.
While this has been worked on and it will be fixed properly, it seems that
our wording could see some refinement and be more vocal about semantic
aspect of these flags as well.

Link: http://lkml.kernel.org/r/20181211143641.3503-2-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Acked-by: Jan Kara <jack@suse.cz>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Mike Rapoport <rppt@linux.ibm.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Paul Oppenheimer <bepvte@gmail.com>
Cc: William Kucharski <william.kucharski@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agoinclude/linux/memory_hotplug.h: remove duplicate declaration of offline_pages()
Wei Yang [Fri, 28 Dec 2018 08:38:13 +0000 (00:38 -0800)]
include/linux/memory_hotplug.h: remove duplicate declaration of offline_pages()

offline_pages() is already declared in this file.

Just remove the duplicated one.

Link: http://lkml.kernel.org/r/20181205031357.24769-1-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm/mmu_notifier: use structure for invalidate_range_start/end calls v2
Jérôme Glisse [Fri, 28 Dec 2018 08:38:09 +0000 (00:38 -0800)]
mm/mmu_notifier: use structure for invalidate_range_start/end calls v2

To avoid having to change many call sites everytime we want to add a
parameter use a structure to group all parameters for the mmu_notifier
invalidate_range_start/end cakks.  No functional changes with this patch.

[akpm@linux-foundation.org: coding style fixes]
Link: http://lkml.kernel.org/r/20181205053628.3210-3-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Acked-by: Christian König <christian.koenig@amd.com>
Acked-by: Jan Kara <jack@suse.cz>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Ross Zwisler <zwisler@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krcmar <rkrcmar@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Felix Kuehling <felix.kuehling@amd.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
From: Jérôme Glisse <jglisse@redhat.com>
Subject: mm/mmu_notifier: use structure for invalidate_range_start/end calls v3

fix build warning in migrate.c when CONFIG_MMU_NOTIFIER=n

Link: http://lkml.kernel.org/r/20181213171330.8489-3-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm/mmu_notifier: use structure for invalidate_range_start/end callback
Jérôme Glisse [Fri, 28 Dec 2018 08:38:05 +0000 (00:38 -0800)]
mm/mmu_notifier: use structure for invalidate_range_start/end callback

Patch series "mmu notifier contextual informations", v2.

This patchset adds contextual information, why an invalidation is
happening, to mmu notifier callback.  This is necessary for user of mmu
notifier that wish to maintains their own data structure without having to
add new fields to struct vm_area_struct (vma).

For instance device can have they own page table that mirror the process
address space.  When a vma is unmap (munmap() syscall) the device driver
can free the device page table for the range.

Today we do not have any information on why a mmu notifier call back is
happening and thus device driver have to assume that it is always an
munmap().  This is inefficient at it means that it needs to re-allocate
device page table on next page fault and rebuild the whole device driver
data structure for the range.

Other use case beside munmap() also exist, for instance it is pointless
for device driver to invalidate the device page table when the
invalidation is for the soft dirtyness tracking.  Or device driver can
optimize away mprotect() that change the page table permission access for
the range.

This patchset enables all this optimizations for device drivers.  I do not
include any of those in this series but another patchset I am posting will
leverage this.

The patchset is pretty simple from a code point of view.  The first two
patches consolidate all mmu notifier arguments into a struct so that it is
easier to add/change arguments.  The last patch adds the contextual
information (munmap, protection, soft dirty, clear, ...).

This patch (of 3):

To avoid having to change many callback definition everytime we want to
add a parameter use a structure to group all parameters for the
mmu_notifier invalidate_range_start/end callback.  No functional changes
with this patch.

[akpm@linux-foundation.org: fix drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c kerneldoc]
Link: http://lkml.kernel.org/r/20181205053628.3210-2-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Acked-by: Jan Kara <jack@suse.cz>
Acked-by: Jason Gunthorpe <jgg@mellanox.com> [infiniband]
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Cc: Ross Zwisler <zwisler@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krcmar <rkrcmar@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Christian Koenig <christian.koenig@amd.com>
Cc: Felix Kuehling <felix.kuehling@amd.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agohwpoison, memory_hotplug: allow hwpoisoned pages to be offlined
Michal Hocko [Fri, 28 Dec 2018 08:38:01 +0000 (00:38 -0800)]
hwpoison, memory_hotplug: allow hwpoisoned pages to be offlined

We have received a bug report that an injected MCE about faulty memory
prevents memory offline to succeed on 4.4 base kernel.  The underlying
reason was that the HWPoison page has an elevated reference count and the
migration keeps failing.  There are two problems with that.  First of all
it is dubious to migrate the poisoned page because we know that accessing
that memory is possible to fail.  Secondly it doesn't make any sense to
migrate a potentially broken content and preserve the memory corruption
over to a new location.

Oscar has found out that 4.4 and the current upstream kernels behave
slightly differently with his simply testcase

===

int main(void)
{
        int ret;
        int i;
        int fd;
        char *array = malloc(4096);
        char *array_locked = malloc(4096);

        fd = open("/tmp/data", O_RDONLY);
        read(fd, array, 4095);

        for (i = 0; i < 4096; i++)
                array_locked[i] = 'd';

        ret = mlock((void *)PAGE_ALIGN((unsigned long)array_locked), sizeof(array_locked));
        if (ret)
                perror("mlock");

        sleep (20);

        ret = madvise((void *)PAGE_ALIGN((unsigned long)array_locked), 4096, MADV_HWPOISON);
        if (ret)
                perror("madvise");

        for (i = 0; i < 4096; i++)
                array_locked[i] = 'd';

        return 0;
}
===

+ offline this memory.

In 4.4 kernels he saw the hwpoisoned page to be returned back to the LRU
list
kernel:  [<ffffffff81019ac9>] dump_trace+0x59/0x340
kernel:  [<ffffffff81019e9a>] show_stack_log_lvl+0xea/0x170
kernel:  [<ffffffff8101ac71>] show_stack+0x21/0x40
kernel:  [<ffffffff8132bb90>] dump_stack+0x5c/0x7c
kernel:  [<ffffffff810815a1>] warn_slowpath_common+0x81/0xb0
kernel:  [<ffffffff811a275c>] __pagevec_lru_add_fn+0x14c/0x160
kernel:  [<ffffffff811a2eed>] pagevec_lru_move_fn+0xad/0x100
kernel:  [<ffffffff811a334c>] __lru_cache_add+0x6c/0xb0
kernel:  [<ffffffff81195236>] add_to_page_cache_lru+0x46/0x70
kernel:  [<ffffffffa02b4373>] extent_readpages+0xc3/0x1a0 [btrfs]
kernel:  [<ffffffff811a16d7>] __do_page_cache_readahead+0x177/0x200
kernel:  [<ffffffff811a18c8>] ondemand_readahead+0x168/0x2a0
kernel:  [<ffffffff8119673f>] generic_file_read_iter+0x41f/0x660
kernel:  [<ffffffff8120e50d>] __vfs_read+0xcd/0x140
kernel:  [<ffffffff8120e9ea>] vfs_read+0x7a/0x120
kernel:  [<ffffffff8121404b>] kernel_read+0x3b/0x50
kernel:  [<ffffffff81215c80>] do_execveat_common.isra.29+0x490/0x6f0
kernel:  [<ffffffff81215f08>] do_execve+0x28/0x30
kernel:  [<ffffffff81095ddb>] call_usermodehelper_exec_async+0xfb/0x130
kernel:  [<ffffffff8161c045>] ret_from_fork+0x55/0x80

And that latter confuses the hotremove path because an LRU page is
attempted to be migrated and that fails due to an elevated reference
count.  It is quite possible that the reuse of the HWPoisoned page is some
kind of fixed race condition but I am not really sure about that.

With the upstream kernel the failure is slightly different.  The page
doesn't seem to have LRU bit set but isolate_movable_page simply fails and
do_migrate_range simply puts all the isolated pages back to LRU and
therefore no progress is made and scan_movable_pages finds same set of
pages over and over again.

Fix both cases by explicitly checking HWPoisoned pages before we even try
to get reference on the page, try to unmap it if it is still mapped.  As
explained by Naoya:

: Hwpoison code never unmapped those for no big reason because
: Ksm pages never dominate memory, so we simply didn't have strong
: motivation to save the pages.

Also put WARN_ON(PageLRU) in case there is a race and we can hit LRU
HWPoison pages which shouldn't happen but I couldn't convince myself about
that.  Naoya has noted the following:

: Theoretically no such gurantee, because try_to_unmap() doesn't have a
: guarantee of success and then memory_failure() returns immediately
: when hwpoison_user_mappings fails.
: Or the following code (comes after hwpoison_user_mappings block) also impli=
: es
: that the target page can still have PageLRU flag.
:
:         /*
:          * Torn down by someone else?
:          */
:         if (PageLRU(p) && !PageSwapCache(p) && p->mapping =3D=3D NULL) {
:                 action_result(pfn, MF_MSG_TRUNCATED_LRU, MF_IGNORED);
:                 res =3D -EBUSY;
:                 goto out;
:         }
:
: So I think it's OK to keep "if (WARN_ON(PageLRU(page)))" block in
: current version of your patch.

Link: http://lkml.kernel.org/r/20181206120135.14079-1-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Oscar Salvador <osalvador@suse.com>
Debugged-by: Oscar Salvador <osalvador@suse.com>
Tested-by: Oscar Salvador <osalvador@suse.com>
Acked-by: David Hildenbrand <david@redhat.com>
Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm, kmemleak: little optimization while scanning
Oscar Salvador [Fri, 28 Dec 2018 08:37:57 +0000 (00:37 -0800)]
mm, kmemleak: little optimization while scanning

kmemleak_scan() goes through all online nodes and tries to scan all used
pages.

We can do better and use pfn_to_online_page(), so in case we have
CONFIG_MEMORY_HOTPLUG, offlined pages will be skiped automatically.  For
boxes where CONFIG_MEMORY_HOTPLUG is not present, pfn_to_online_page()
will fallback to pfn_valid().

Another little optimization is to check if the page belongs to the node we
are currently checking, so in case we have nodes interleaved we will not
check the same pfn multiple times.

I ran some tests:

Add some memory to node1 and node2 making it interleaved:

(qemu) object_add memory-backend-ram,id=ram0,size=1G
(qemu) device_add pc-dimm,id=dimm0,memdev=ram0,node=1
(qemu) object_add memory-backend-ram,id=ram1,size=1G
(qemu) device_add pc-dimm,id=dimm1,memdev=ram1,node=2
(qemu) object_add memory-backend-ram,id=ram2,size=1G
(qemu) device_add pc-dimm,id=dimm2,memdev=ram2,node=1

Then, we offline that memory:
 # for i in {32..39} ; do echo "offline" > /sys/devices/system/node/node1/memory$i/state;done
 # for i in {48..55} ; do echo "offline" > /sys/devices/system/node/node1/memory$i/state;don
 # for i in {40..47} ; do echo "offline" > /sys/devices/system/node/node2/memory$i/state;done

And we run kmemleak_scan:

 # echo "scan" > /sys/kernel/debug/kmemleak

before the patch:

kmemleak: time spend: 41596 us

after the patch:

kmemleak: time spend: 34899 us

[akpm@linux-foundation.org: remove stray newline, per Oscar]
Link: http://lkml.kernel.org/r/20181206131918.25099-1-osalvador@suse.de
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Suggested-by: Michal Hocko <mhocko@suse.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agolib/ioremap: ensure break-before-make is used for huge p4d mappings
Will Deacon [Fri, 28 Dec 2018 08:37:53 +0000 (00:37 -0800)]
lib/ioremap: ensure break-before-make is used for huge p4d mappings

Whilst no architectures actually enable support for huge p4d mappings in
the vmap area, the code that is implemented should be using
break-before-make, as we do for pud and pmd huge entries.

Link: http://lkml.kernel.org/r/1544120495-17438-6-git-send-email-will.deacon@arm.com
Signed-off-by: Will Deacon <will.deacon@arm.com>
Reviewed-by: Toshi Kani <toshi.kani@hpe.com>
Cc: Chintan Pandya <cpandya@codeaurora.org>
Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agolib/ioremap: ensure phys_addr actually corresponds to a physical address
Will Deacon [Fri, 28 Dec 2018 08:37:49 +0000 (00:37 -0800)]
lib/ioremap: ensure phys_addr actually corresponds to a physical address

The current ioremap() code uses a phys_addr variable at each level of page
table, which is confusingly offset by subtracting the base virtual address
being mapped so that adding the current virtual address back on when
iterating through the page table entries gives back the corresponding
physical address.

This is fairly confusing and results in all users of phys_addr having to
add the current virtual address back on.  Instead, this patch just updates
phys_addr when iterating over the page table entries, ensuring that it's
always up-to-date and doesn't require explicit offsetting.

Link: http://lkml.kernel.org/r/1544120495-17438-5-git-send-email-will.deacon@arm.com
Signed-off-by: Will Deacon <will.deacon@arm.com>
Tested-by: Sean Christopherson <sean.j.christopherson@intel.com>
Reviewed-by: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: Chintan Pandya <cpandya@codeaurora.org>
Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agox86/pgtable: drop pXd_none() checks from pXd_free_pYd_table()
Will Deacon [Fri, 28 Dec 2018 08:37:45 +0000 (00:37 -0800)]
x86/pgtable: drop pXd_none() checks from pXd_free_pYd_table()

The core code already has a check for pXd_none(), so remove it from the
architecture implementation.

Link: http://lkml.kernel.org/r/1544120495-17438-4-git-send-email-will.deacon@arm.com
Signed-off-by: Will Deacon <will.deacon@arm.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Toshi Kani <toshi.kani@hpe.com>
Cc: Chintan Pandya <cpandya@codeaurora.org>
Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agoarm64: mmu: drop pXd_present() checks from pXd_free_pYd_table()
Will Deacon [Fri, 28 Dec 2018 08:37:42 +0000 (00:37 -0800)]
arm64: mmu: drop pXd_present() checks from pXd_free_pYd_table()

The core code already has a check for pXd_none(), so remove it from the
architecture implementation.

Link: http://lkml.kernel.org/r/1544120495-17438-3-git-send-email-will.deacon@arm.com
Signed-off-by: Will Deacon <will.deacon@arm.com>
Cc: Chintan Pandya <cpandya@codeaurora.org>
Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agoioremap: rework pXd_free_pYd_page() API
Will Deacon [Fri, 28 Dec 2018 08:37:38 +0000 (00:37 -0800)]
ioremap: rework pXd_free_pYd_page() API

The recently merged API for ensuring break-before-make on page-table
entries when installing huge mappings in the vmalloc/ioremap region is
fairly counter-intuitive, resulting in the arch freeing functions (e.g.
pmd_free_pte_page()) being called even on entries that aren't present.
This resulted in a minor bug in the arm64 implementation, giving rise to
spurious VM_WARN messages.

This patch moves the pXd_present() checks out into the core code,
refactoring the callsites at the same time so that we avoid the complex
conjunctions when determining whether or not we can put down a huge
mapping.

Link: http://lkml.kernel.org/r/1544120495-17438-2-git-send-email-will.deacon@arm.com
Signed-off-by: Will Deacon <will.deacon@arm.com>
Reviewed-by: Toshi Kani <toshi.kani@hpe.com>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Chintan Pandya <cpandya@codeaurora.org>
Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Michal Hocko <mhocko@suse.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm/filemap.c: remove useless check in pagecache_get_page()
Kirill Tkhai [Fri, 28 Dec 2018 08:37:35 +0000 (00:37 -0800)]
mm/filemap.c: remove useless check in pagecache_get_page()

page always is not NULL, so we may remove this useless check.

Link: http://lkml.kernel.org/r/154419752044.18559.2452963074922917720.stgit@localhost.localdomain
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Acked-by: Cyrill Gorcunov <gorcunov@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months ago/proc/kpagecount: return 0 for special pages that are never mapped
Anthony Yznaga [Fri, 28 Dec 2018 08:37:31 +0000 (00:37 -0800)]
/proc/kpagecount: return 0 for special pages that are never mapped

Certain pages that are never mapped to userspace have a type indicated in
the page_type field of their struct pages (e.g.  PG_buddy).  page_type
overlaps with _mapcount so set the count to 0 and avoid calling
page_mapcount() for these pages.

[anthony.yznaga@oracle.com: incorporate feedback from Matthew Wilcox]
Link: http://lkml.kernel.org/r/1544481313-27318-1-git-send-email-anthony.yznaga@oracle.com
Link: http://lkml.kernel.org/r/1543963526-27917-1-git-send-email-anthony.yznaga@oracle.com
Signed-off-by: Anthony Yznaga <anthony.yznaga@oracle.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Matthew Wilcox <willy@infradead.org>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: David Rientjes <rientjes@google.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Miles Chen <miles.chen@mediatek.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agotools/vm/page-types.c: fix "kpagecount returned fewer pages than expected" failures
Anthony Yznaga [Fri, 28 Dec 2018 08:37:27 +0000 (00:37 -0800)]
tools/vm/page-types.c: fix "kpagecount returned fewer pages than expected" failures

Because kpagecount_read() fakes success if map counts are not being
collected, clamp the page count passed to it by walk_pfn() to the pages
value returned by the preceding call to kpageflags_read().

Link: http://lkml.kernel.org/r/1543962269-26116-1-git-send-email-anthony.yznaga@oracle.com
Fixes: 7f1d23e60718 ("tools/vm/page-types.c: include shared map counts")
Signed-off-by: Anthony Yznaga <anthony.yznaga@oracle.com>
Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: David Rientjes <rientjes@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm/page_alloc.c: drop uneeded __meminit and __meminitdata
Oscar Salvador [Fri, 28 Dec 2018 08:37:24 +0000 (00:37 -0800)]
mm/page_alloc.c: drop uneeded __meminit and __meminitdata

Since commit 03e85f9d5f1 ("mm/page_alloc: Introduce
free_area_init_core_hotplug"), some functions changed to only be called
during system initialization.  Concretly, free_area_init_node() and the
functions that hang from it.

Also, some variables are no longer used after the system has gone
through initialization.  So this could be considered as a late clean-up
for that patch.

This patch changes the functions from __meminit to __init, and the
variables from __meminitdata to __initdata.

In return, we get some KBs back:

Before:
  Freeing unused kernel image memory: 2472K

After:
  Freeing unused kernel image memory: 2480K

Link: http://lkml.kernel.org/r/20181204111507.4808-1-osalvador@suse.de
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Pavel Tatashin <pavel.tatashin@microsoft.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm/page-writeback.c: don't break integrity writeback on ->writepage() error
Brian Foster [Fri, 28 Dec 2018 08:37:20 +0000 (00:37 -0800)]
mm/page-writeback.c: don't break integrity writeback on ->writepage() error

write_cache_pages() is used in both background and integrity writeback
scenarios by various filesystems.  Background writeback is mostly
concerned with cleaning a certain number of dirty pages based on various
mm heuristics.  It may not write the full set of dirty pages or wait for
I/O to complete.  Integrity writeback is responsible for persisting a set
of dirty pages before the writeback job completes.  For example, an
fsync() call must perform integrity writeback to ensure data is on disk
before the call returns.

write_cache_pages() unconditionally breaks out of its processing loop in
the event of a ->writepage() error.  This is fine for background
writeback, which had no strict requirements and will eventually come
around again.  This can cause problems for integrity writeback on
filesystems that might need to clean up state associated with failed page
writeouts.  For example, XFS performs internal delayed allocation
accounting before returning a ->writepage() error, where applicable.  If
the current writeback happens to be associated with an unmount and
write_cache_pages() completes the writeback prematurely due to error, the
filesystem is unmounted in an inconsistent state if dirty+delalloc pages
still exist.

To handle this problem, update write_cache_pages() to always process the
full set of pages for integrity writeback regardless of ->writepage()
errors.  Save the first encountered error and return it to the caller once
complete.  This facilitates XFS (or any other fs that expects integrity
writeback to process the entire set of dirty pages) to clean up its
internal state completely in the event of persistent mapping errors.
Background writeback continues to exit on the first error encountered.

[akpm@linux-foundation.org: fix typo in comment]
Link: http://lkml.kernel.org/r/20181116134304.32440-1-bfoster@redhat.com
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agolib/show_mem.c: drop pgdat_resize_lock in show_mem()
Wei Yang [Fri, 28 Dec 2018 08:37:16 +0000 (00:37 -0800)]
lib/show_mem.c: drop pgdat_resize_lock in show_mem()

Function show_mem() is used to print system memory status when user
requires or fail to allocate memory.  Generally, this is a best effort
information so any races with memory hotplug (or very theoretically an
early initialization) should be tolerable and the worst that could happen
is to print an imprecise node state.

Drop the resize lock because this is the only place which might hold the
lock from the interrupt context and so all other callers might use a
simple spinlock.  Even though this doesn't solve any real issue it makes
the code easier to follow and tiny more effective.

Link: http://lkml.kernel.org/r/20181129235532.9328-1-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm/hmm.c: remove set but not used variable 'devmem'
YueHaibing [Fri, 28 Dec 2018 08:37:13 +0000 (00:37 -0800)]
mm/hmm.c: remove set but not used variable 'devmem'

Fixes gcc '-Wunused-but-set-variable' warning:

mm/hmm.c: In function 'hmm_devmem_ref_kill':
mm/hmm.c:995:21: warning:
 variable 'devmem' set but not used [-Wunused-but-set-variable]

It not used any more since 35d39f953d4e ("mm, hmm: replace
hmm_devmem_pages_create() with devm_memremap_pages()")

Link: http://lkml.kernel.org/r/1543629971-128377-1-git-send-email-yuehaibing@huawei.com
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Reviewed-by: Reviewed-by: Jérôme Glisse <jglisse@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm, hotplug: move init_currently_empty_zone() under zone_span_lock protection
Wei Yang [Fri, 28 Dec 2018 08:37:10 +0000 (00:37 -0800)]
mm, hotplug: move init_currently_empty_zone() under zone_span_lock protection

During online_pages phase, pgdat->nr_zones will be updated in case this
zone is empty.

Currently the online_pages phase is protected by the global locks
(device_device_hotplug_lock and mem_hotplug_lock), which ensures there is
no contention during the update of nr_zones.

These global locks introduces scalability issues (especially the second
one), which slow down code relying on get_online_mems().  This is also a
preparation for not having to rely on get_online_mems() but instead some
more fine grained locks.

The patch moves init_currently_empty_zone under both zone_span_writelock
and pgdat_resize_lock because both the pgdat state is changed (nr_zones)
and the zone's start_pfn.  Also this patch changes the documentation of
node_size_lock to include the protection of nr_zones.

Link: http://lkml.kernel.org/r/20181203205016.14123-1-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm, sparse: pass nid instead of pgdat to sparse_add_one_section()
Wei Yang [Fri, 28 Dec 2018 08:37:06 +0000 (00:37 -0800)]
mm, sparse: pass nid instead of pgdat to sparse_add_one_section()

Since the information needed in sparse_add_one_section() is node id to
allocate proper memory, it is not necessary to pass its pgdat.

This patch changes the prototype of sparse_add_one_section() to pass node
id directly.  This is intended to reduce misleading that
sparse_add_one_section() would touch pgdat.

Link: http://lkml.kernel.org/r/20181204085657.20472-2-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm, sparse: drop pgdat_resize_lock in sparse_add/remove_one_section()
Wei Yang [Fri, 28 Dec 2018 08:37:02 +0000 (00:37 -0800)]
mm, sparse: drop pgdat_resize_lock in sparse_add/remove_one_section()

pgdat_resize_lock is used to protect pgdat's memory region information
like: node_start_pfn, node_present_pages, etc.  While in function
sparse_add/remove_one_section(), pgdat_resize_lock is used to protect
initialization/release of one mem_section.  This looks not proper.

These code paths are currently protected by mem_hotplug_lock currently but
should there ever be any reason for locking at the sparse layer a
dedicated lock should be introduced.

Following is the current call trace of sparse_add/remove_one_section()

    mem_hotplug_begin()
    arch_add_memory()
       add_pages()
           __add_pages()
               __add_section()
                   sparse_add_one_section()
    mem_hotplug_done()

    mem_hotplug_begin()
    arch_remove_memory()
        __remove_pages()
            __remove_section()
                sparse_remove_one_section()
    mem_hotplug_done()

The comment above the pgdat_resize_lock also mentions "Holding this will
also guarantee that any pfn_valid() stays that way.", which is true with
the current implementation and false after this patch.  But current
implementation doesn't meet this comment.  There isn't any pfn walkers to
take the lock so this looks like a relict from the past.  This patch also
removes this comment.

[richard.weiyang@gmail.com: v4]
Link: http://lkml.kernel.org/r/20181204085657.20472-1-richard.weiyang@gmail.com
[mhocko@suse.com: changelog suggestion]
Link: http://lkml.kernel.org/r/20181128091243.19249-1-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm: remove pte_lock_deinit()
Yu Zhao [Fri, 28 Dec 2018 08:36:58 +0000 (00:36 -0800)]
mm: remove pte_lock_deinit()

Pagetable page doesn't touch page->mapping or have any used field that
overlaps with it.  No need to clear mapping in dtor.  In fact, doing so
might mask problems that otherwise would be detected by bad_page().

Link: http://lkml.kernel.org/r/20181128235525.58780-1-yuzhao@google.com
Signed-off-by: Yu Zhao <yuzhao@google.com>
Reviewed-by: Matthew Wilcox <willy@infradead.org>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Pavel Tatashin <pasha.tatashin@oracle.com>
Cc: Souptick Joarder <jrdr.linux@gmail.com>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Keith Busch <keith.busch@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agozram: writeback throttle
Minchan Kim [Fri, 28 Dec 2018 08:36:54 +0000 (00:36 -0800)]
zram: writeback throttle

If there are lots of write IO with flash device, it could have a
wearout problem of storage. To overcome the problem, admin needs
to design write limitation to guarantee flash health
for entire product life.

This patch creates a new knob "writeback_limit" for zram.

writeback_limit's default value is 0 so that it doesn't limit
any writeback. If admin want to measure writeback count in a
certain period, he could know it via /sys/block/zram0/bd_stat's
3rd column.

If admin want to limit writeback as per-day 400M, he could do it
like below.

MB_SHIFT=20
4K_SHIFT=12
echo $((400<<MB_SHIFT>>4K_SHIFT)) > \
/sys/block/zram0/writeback_limit.

If admin want to allow further write again, he could do it like below

echo 0 > /sys/block/zram0/writeback_limit

If admin want to see remaining writeback budget,

cat /sys/block/zram0/writeback_limit

The writeback_limit count will reset whenever you reset zram (e.g., system
reboot, echo 1 > /sys/block/zramX/reset) so keeping how many of writeback
happened until you reset the zram to allocate extra writeback budget in
next setting is user's job.

[minchan@kernel.org: v4]
Link: http://lkml.kernel.org/r/20181203024045.153534-8-minchan@kernel.org
Link: http://lkml.kernel.org/r/20181127055429.251614-8-minchan@kernel.org
Signed-off-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Joey Pabalinas <joeypabalinas@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agozram: add bd_stat statistics
Minchan Kim [Fri, 28 Dec 2018 08:36:51 +0000 (00:36 -0800)]
zram: add bd_stat statistics

bd_stat represents things that happened in the backing device.  Currently
it supports bd_counts, bd_reads and bd_writes which are helpful to
understand wearout of flash and memory saving.

[minchan@kernel.org: v4]
Link: http://lkml.kernel.org/r/20181203024045.153534-7-minchan@kernel.org
Link: http://lkml.kernel.org/r/20181127055429.251614-7-minchan@kernel.org
Signed-off-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Joey Pabalinas <joeypabalinas@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agozram: support idle/huge page writeback
Minchan Kim [Fri, 28 Dec 2018 08:36:47 +0000 (00:36 -0800)]
zram: support idle/huge page writeback

Add a new feature "zram idle/huge page writeback".  In the zram-swap use
case, zram usually has many idle/huge swap pages.  It's pointless to keep
them in memory (ie, zram).

To solve this problem, this feature introduces idle/huge page writeback to
the backing device so the goal is to save more memory space on embedded
systems.

Normal sequence to use idle/huge page writeback feature is as follows,

while (1) {
        # mark allocated zram slot to idle
        echo all > /sys/block/zram0/idle
        # leave system working for several hours
        # Unless there is no access for some blocks on zram,
# they are still IDLE marked pages.

        echo "idle" > /sys/block/zram0/writeback
or/and
echo "huge" > /sys/block/zram0/writeback
        # write the IDLE or/and huge marked slot into backing device
# and free the memory.
}

Per the discussion at
https://lore.kernel.org/lkml/20181122065926.GG3441@jagdpanzerIV/T/#u,

This patch removes direct incommpressibe page writeback feature
(d2afd25114f4 ("zram: write incompressible pages to backing device")).

Below concerns from Sergey:
== &< ==

"IDLE writeback" is superior to "incompressible writeback".

"incompressible writeback" is completely unpredictable and uncontrollable;
it depens on data patterns and compression algorithms.  While "IDLE
writeback" is predictable.

I even suspect, that, *ideally*, we can remove "incompressible writeback".
"IDLE pages" is a super set which also includes "incompressible" pages.
So, technically, we still can do "incompressible writeback" from "IDLE
writeback" path; but a much more reasonable one, based on a page idling
period.

I understand that you want to keep "direct incompressible writeback"
around.  ZRAM is especially popular on devices which do suffer from flash
wearout, so I can see "incompressible writeback" path becoming a dead
code, long term.

== &< ==

Below concerns from Minchan:
== &< ==

My concern is if we enable CONFIG_ZRAM_WRITEBACK in this implementation,
both hugepage/idlepage writeck will turn on.  However someuser want to
enable only idlepage writeback so we need to introduce turn on/off knob
for hugepage or new CONFIG_ZRAM_IDLEPAGE_WRITEBACK for those usecase.  I
don't want to make it complicated *if possible*.

Long term, I imagine we need to make VM aware of new swap hierarchy a
little bit different with as-is.  For example, first high priority swap
can return -EIO or -ENOCOMP, swap try to fallback to next lower priority
swap device.  With that, hugepage writeback will work tranparently.

So we could regard it as regression because incompressible pages doesn't
go to backing storage automatically.  Instead, user should do it via "echo
huge" > /sys/block/zram/writeback" manually.

== &< ==

Link: http://lkml.kernel.org/r/20181127055429.251614-6-minchan@kernel.org
Signed-off-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Joey Pabalinas <joeypabalinas@gmail.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agozram: introduce ZRAM_IDLE flag
Minchan Kim [Fri, 28 Dec 2018 08:36:44 +0000 (00:36 -0800)]
zram: introduce ZRAM_IDLE flag

To support idle page writeback with upcoming patches, this patch
introduces a new ZRAM_IDLE flag.

Userspace can mark zram slots as "idle" via
"echo all > /sys/block/zramX/idle"
which marks every allocated zram slot as ZRAM_IDLE.
User could see it by /sys/kernel/debug/zram/zram0/block_state.

          300    75.033841 ...i
          301    63.806904 s..i
          302    63.806919 ..hi

Once there is IO for the slot, the mark will be disappeared.

  300    75.033841 ...
          301    63.806904 s..i
          302    63.806919 ..hi

Therefore, 300th block is idle zpage. With this feature,
user can how many zram has idle pages which are waste of memory.

Link: http://lkml.kernel.org/r/20181127055429.251614-5-minchan@kernel.org
Signed-off-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reviewed-by: Joey Pabalinas <joeypabalinas@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agozram: refactor flags and writeback stuff
Minchan Kim [Fri, 28 Dec 2018 08:36:40 +0000 (00:36 -0800)]
zram: refactor flags and writeback stuff

Rename some variables and restructure some code for better readability in
writeback and zs_free_page.

Link: http://lkml.kernel.org/r/20181127055429.251614-4-minchan@kernel.org
Signed-off-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reviewed-by: Joey Pabalinas <joeypabalinas@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agozram: fix double free backing device
Minchan Kim [Fri, 28 Dec 2018 08:36:37 +0000 (00:36 -0800)]
zram: fix double free backing device

If blkdev_get fails, we shouldn't do blkdev_put.  Otherwise, kernel emits
below log.  This patch fixes it.

  WARNING: CPU: 0 PID: 1893 at fs/block_dev.c:1828 blkdev_put+0x105/0x120
  Modules linked in:
  CPU: 0 PID: 1893 Comm: swapoff Not tainted 4.19.0+ #453
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
  RIP: 0010:blkdev_put+0x105/0x120
  Call Trace:
    __x64_sys_swapoff+0x46d/0x490
    do_syscall_64+0x5a/0x190
    entry_SYSCALL_64_after_hwframe+0x49/0xbe
  irq event stamp: 4466
  hardirqs last  enabled at (4465):  __free_pages_ok+0x1e3/0x490
  hardirqs last disabled at (4466):  trace_hardirqs_off_thunk+0x1a/0x1c
  softirqs last  enabled at (3420):  __do_softirq+0x333/0x446
  softirqs last disabled at (3407):  irq_exit+0xd1/0xe0

Link: http://lkml.kernel.org/r/20181127055429.251614-3-minchan@kernel.org
Signed-off-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reviewed-by: Joey Pabalinas <joeypabalinas@gmail.com>
Cc: <stable@vger.kernel.org> [4.14+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agozram: fix lockdep warning of free block handling
Minchan Kim [Fri, 28 Dec 2018 08:36:33 +0000 (00:36 -0800)]
zram: fix lockdep warning of free block handling

Patch series "zram idle page writeback", v3.

Inherently, swap device has many idle pages which are rare touched since
it was allocated.  It is never problem if we use storage device as swap.
However, it's just waste for zram-swap.

This patchset supports zram idle page writeback feature.

* Admin can define what is idle page "no access since X time ago"
* Admin can define when zram should writeback them
* Admin can define when zram should stop writeback to prevent wearout

Details are in each patch's description.

This patch (of 7):

  ================================
  WARNING: inconsistent lock state
  4.19.0+ #390 Not tainted
  --------------------------------
  inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.
  zram_verify/2095 [HC0[0]:SC1[1]:HE1:SE0] takes:
  00000000b1828693 (&(&zram->bitmap_lock)->rlock){+.?.}, at: put_entry_bdev+0x1e/0x50
  {SOFTIRQ-ON-W} state was registered at:
    _raw_spin_lock+0x2c/0x40
    zram_make_request+0x755/0xdc9
    generic_make_request+0x373/0x6a0
    submit_bio+0x6c/0x140
    __swap_writepage+0x3a8/0x480
    shrink_page_list+0x1102/0x1a60
    shrink_inactive_list+0x21b/0x3f0
    shrink_node_memcg.constprop.99+0x4f8/0x7e0
    shrink_node+0x7d/0x2f0
    do_try_to_free_pages+0xe0/0x300
    try_to_free_pages+0x116/0x2b0
    __alloc_pages_slowpath+0x3f4/0xf80
    __alloc_pages_nodemask+0x2a2/0x2f0
    __handle_mm_fault+0x42e/0xb50
    handle_mm_fault+0x55/0xb0
    __do_page_fault+0x235/0x4b0
    page_fault+0x1e/0x30
  irq event stamp: 228412
  hardirqs last  enabled at (228412): [<ffffffff98245846>] __slab_free+0x3e6/0x600
  hardirqs last disabled at (228411): [<ffffffff98245625>] __slab_free+0x1c5/0x600
  softirqs last  enabled at (228396): [<ffffffff98e0031e>] __do_softirq+0x31e/0x427
  softirqs last disabled at (228403): [<ffffffff98072051>] irq_exit+0xd1/0xe0

  other info that might help us debug this:
   Possible unsafe locking scenario:

         CPU0
         ----
    lock(&(&zram->bitmap_lock)->rlock);
    <Interrupt>
      lock(&(&zram->bitmap_lock)->rlock);

   *** DEADLOCK ***

  no locks held by zram_verify/2095.

  stack backtrace:
  CPU: 5 PID: 2095 Comm: zram_verify Not tainted 4.19.0+ #390
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014
  Call Trace:
   <IRQ>
   dump_stack+0x67/0x9b
   print_usage_bug+0x1bd/0x1d3
   mark_lock+0x4aa/0x540
   __lock_acquire+0x51d/0x1300
   lock_acquire+0x90/0x180
   _raw_spin_lock+0x2c/0x40
   put_entry_bdev+0x1e/0x50
   zram_free_page+0xf6/0x110
   zram_slot_free_notify+0x42/0xa0
   end_swap_bio_read+0x5b/0x170
   blk_update_request+0x8f/0x340
   scsi_end_request+0x2c/0x1e0
   scsi_io_completion+0x98/0x650
   blk_done_softirq+0x9e/0xd0
   __do_softirq+0xcc/0x427
   irq_exit+0xd1/0xe0
   do_IRQ+0x93/0x120
   common_interrupt+0xf/0xf
   </IRQ>

With writeback feature, zram_slot_free_notify could be called in softirq
context by end_swap_bio_read.  However, bitmap_lock is not aware of that
so lockdep yell out:

  get_entry_bdev
  spin_lock(bitmap->lock);
  irq
  softirq
  end_swap_bio_read
  zram_slot_free_notify
  zram_slot_lock <-- deadlock prone
  zram_free_page
  put_entry_bdev
  spin_lock(bitmap->lock); <-- deadlock prone

With akpm's suggestion (i.e.  bitmap operation is already atomic), we
could remove bitmap lock.  It might fail to find a empty slot if serious
contention happens.  However, it's not severe problem because huge page
writeback has already possiblity to fail if there is severe memory
pressure.  Worst case is just keeping the incompressible in memory, not
storage.

The other problem is zram_slot_lock in zram_slot_slot_free_notify.  To
make it safe is this patch introduces zram_slot_trylock where
zram_slot_free_notify uses it.  Although it's rare to be contented, this
patch adds new debug stat "miss_free" to keep monitoring how often it
happens.

Link: http://lkml.kernel.org/r/20181127055429.251614-2-minchan@kernel.org
Signed-off-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reviewed-by: Joey Pabalinas <joeypabalinas@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm/memblock.c: skip kmemleak for kasan_init()
Qian Cai [Fri, 28 Dec 2018 08:36:29 +0000 (00:36 -0800)]
mm/memblock.c: skip kmemleak for kasan_init()

Kmemleak does not play well with KASAN (tested on both HPE Apollo 70 and
Huawei TaiShan 2280 aarch64 servers).

After calling start_kernel()->setup_arch()->kasan_init(), kmemleak early
log buffer went from something like 280 to 260000 which caused kmemleak
disabled and crash dump memory reservation failed.  The multitude of
kmemleak_alloc() calls is from nested loops while KASAN is setting up full
memory mappings, so let early kmemleak allocations skip those
memblock_alloc_internal() calls came from kasan_init() given that those
early KASAN memory mappings should not reference to other memory.  Hence,
no kmemleak false positives.

kasan_init
  kasan_map_populate [1]
    kasan_pgd_populate [2]
      kasan_pud_populate [3]
        kasan_pmd_populate [4]
          kasan_pte_populate [5]
            kasan_alloc_zeroed_page
              memblock_alloc_try_nid
                memblock_alloc_internal
                  kmemleak_alloc

[1] for_each_memblock(memory, reg)
[2] while (pgdp++, addr = next, addr != end)
[3] while (pudp++, addr = next, addr != end && pud_none(READ_ONCE(*pudp)))
[4] while (pmdp++, addr = next, addr != end && pmd_none(READ_ONCE(*pmdp)))
[5] while (ptep++, addr = next, addr != end && pte_none(READ_ONCE(*ptep)))

Link: http://lkml.kernel.org/r/1543442925-17794-1-git-send-email-cai@gmx.us
Signed-off-by: Qian Cai <cai@gmx.us>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agokernel, resource: check for IORESOURCE_SYSRAM in release_mem_region_adjustable
Oscar Salvador [Fri, 28 Dec 2018 08:36:26 +0000 (00:36 -0800)]
kernel, resource: check for IORESOURCE_SYSRAM in release_mem_region_adjustable

This is a preparation for the next patch.

Currently, we only call release_mem_region_adjustable() in __remove_pages
if the zone is not ZONE_DEVICE, because resources that belong to HMM/devm
are being released by themselves with devm_release_mem_region.

Since we do not want to touch any zone/page stuff during the removing of
the memory (but during the offlining), we do not want to check for the
zone here.  So we need another way to tell release_mem_region_adjustable()
to not realease the resource in case it belongs to HMM/devm.

HMM/devm acquires/releases a resource through
devm_request_mem_region/devm_release_mem_region.

These resources have the flag IORESOURCE_MEM, while resources acquired by
hot-add memory path (register_memory_resource()) contain
IORESOURCE_SYSTEM_RAM.

So, we can check for this flag in release_mem_region_adjustable, and if
the resource does not contain such flag, we know that we are dealing with
a HMM/devm resource, so we can back off.

Link: http://lkml.kernel.org/r/20181127162005.15833-3-osalvador@suse.de
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Oscar Salvador <osalvador@suse.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm, memory_hotplug: add nid parameter to arch_remove_memory
Oscar Salvador [Fri, 28 Dec 2018 08:36:22 +0000 (00:36 -0800)]
mm, memory_hotplug: add nid parameter to arch_remove_memory

Patch series "Do not touch pages in hot-remove path", v2.

This patchset aims for two things:

 1) A better definition about offline and hot-remove stage
 2) Solving bugs where we can access non-initialized pages
    during hot-remove operations [2] [3].

This is achieved by moving all page/zone handling to the offline
stage, so we do not need to access pages when hot-removing memory.

[1] https://patchwork.kernel.org/cover/10691415/
[2] https://patchwork.kernel.org/patch/10547445/
[3] https://www.spinics.net/lists/linux-mm/msg161316.html

This patch (of 5):

This is a preparation for the following-up patches.  The idea of passing
the nid is that it will allow us to get rid of the zone parameter
afterwards.

Link: http://lkml.kernel.org/r/20181127162005.15833-2-osalvador@suse.de
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm: check nr_initialised with PAGES_PER_SECTION directly in defer_init()
Wei Yang [Fri, 28 Dec 2018 08:36:18 +0000 (00:36 -0800)]
mm: check nr_initialised with PAGES_PER_SECTION directly in defer_init()

When DEFERRED_STRUCT_PAGE_INIT is configured, only the first section of
each node's highest zone is initialized before defer stage.

static_init_pgcnt is used to store the number of pages like this:

    pgdat->static_init_pgcnt = min_t(unsigned long, PAGES_PER_SECTION,
                                              pgdat->node_spanned_pages);

because we don't want to overflow zone's range.

But this is not necessary, since defer_init() is called like this:

  memmap_init_zone()
    for pfn in [start_pfn, end_pfn)
      defer_init(pfn, end_pfn)

In case (pgdat->node_spanned_pages < PAGES_PER_SECTION), the loop would
stop before calling defer_init().

BTW, comparing PAGES_PER_SECTION with node_spanned_pages is not correct,
since nr_initialised is zone based instead of node based.  Even
node_spanned_pages is bigger than PAGES_PER_SECTION, its highest zone
would have pages less than PAGES_PER_SECTION.

Link: http://lkml.kernel.org/r/20181122094807.6985-1-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Cc: Pavel Tatashin <pasha.tatashin@oracle.com>
Cc: Oscar Salvador <osalvador@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm: put_and_wait_on_page_locked() while page is migrated
Hugh Dickins [Fri, 28 Dec 2018 08:36:14 +0000 (00:36 -0800)]
mm: put_and_wait_on_page_locked() while page is migrated

Waiting on a page migration entry has used wait_on_page_locked() all along
since 2006: but you cannot safely wait_on_page_locked() without holding a
reference to the page, and that extra reference is enough to make
migrate_page_move_mapping() fail with -EAGAIN, when a racing task faults
on the entry before migrate_page_move_mapping() gets there.

And that failure is retried nine times, amplifying the pain when trying to
migrate a popular page.  With a single persistent faulter, migration
sometimes succeeds; with two or three concurrent faulters, success becomes
much less likely (and the more the page was mapped, the worse the overhead
of unmapping and remapping it on each try).

This is especially a problem for memory offlining, where the outer level
retries forever (or until terminated from userspace), because a heavy
refault workload can trigger an endless loop of migration failures.
wait_on_page_locked() is the wrong tool for the job.

David Herrmann (but was he the first?) noticed this issue in 2014:
https://marc.info/?l=linux-mm&m=140110465608116&w=2

Tim Chen started a thread in August 2017 which appears relevant:
https://marc.info/?l=linux-mm&m=150275941014915&w=2 where Kan Liang went
on to implicate __migration_entry_wait():
https://marc.info/?l=linux-mm&m=150300268411980&w=2 and the thread ended
up with the v4.14 commits: 2554db916586 ("sched/wait: Break up long wake
list walk") 11a19c7b099f ("sched/wait: Introduce wakeup boomark in
wake_up_page_bit")

Baoquan He reported "Memory hotplug softlock issue" 14 November 2018:
https://marc.info/?l=linux-mm&m=154217936431300&w=2

We have all assumed that it is essential to hold a page reference while
waiting on a page lock: partly to guarantee that there is still a struct
page when MEMORY_HOTREMOVE is configured, but also to protect against
reuse of the struct page going to someone who then holds the page locked
indefinitely, when the waiter can reasonably expect timely unlocking.

But in fact, so long as wait_on_page_bit_common() does the put_page(), and
is careful not to rely on struct page contents thereafter, there is no
need to hold a reference to the page while waiting on it.  That does mean
that this case cannot go back through the loop: but that's fine for the
page migration case, and even if used more widely, is limited by the "Stop
walking if it's locked" optimization in wake_page_function().

Add interface put_and_wait_on_page_locked() to do this, using "behavior"
enum in place of "lock" arg to wait_on_page_bit_common() to implement it.
No interruptible or killable variant needed yet, but they might follow: I
have a vague notion that reporting -EINTR should take precedence over
return from wait_on_page_bit_common() without knowing the page state, so
arrange it accordingly - but that may be nothing but pedantic.

__migration_entry_wait() still has to take a brief reference to the page,
prior to calling put_and_wait_on_page_locked(): but now that it is dropped
before waiting, the chance of impeding page migration is very much
reduced.  Should we perhaps disable preemption across this?

shrink_page_list()'s __ClearPageLocked(): that was a surprise!  This
survived a lot of testing before that showed up.  PageWaiters may have
been set by wait_on_page_bit_common(), and the reference dropped, just
before shrink_page_list() succeeds in freezing its last page reference: in
such a case, unlock_page() must be used.  Follow the suggestion from
Michal Hocko, just revert a978d6f52106 ("mm: unlockless reclaim") now:
that optimization predates PageWaiters, and won't buy much these days; but
we can reinstate it for the !PageWaiters case if anyone notices.

It does raise the question: should vmscan.c's is_page_cache_freeable() and
__remove_mapping() now treat a PageWaiters page as if an extra reference
were held?  Perhaps, but I don't think it matters much, since
shrink_page_list() already had to win its trylock_page(), so waiters are
not very common there: I noticed no difference when trying the bigger
change, and it's surely not needed while put_and_wait_on_page_locked() is
only used for page migration.

[willy@infradead.org: add put_and_wait_on_page_locked() kerneldoc]
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.1811261121330.1116@eggly.anvils
Signed-off-by: Hugh Dickins <hughd@google.com>
Reported-by: Baoquan He <bhe@redhat.com>
Tested-by: Baoquan He <bhe@redhat.com>
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Baoquan He <bhe@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: David Herrmann <dh.herrmann@gmail.com>
Cc: Tim Chen <tim.c.chen@linux.intel.com>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: Nick Piggin <npiggin@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm, oom: add oom victim's memcg to the oom context information
yuzhoujian [Fri, 28 Dec 2018 08:36:10 +0000 (00:36 -0800)]
mm, oom: add oom victim's memcg to the oom context information

The current oom report doesn't display victim's memcg context during the
global OOM situation.  While this information is not strictly needed, it
can be really helpful for containerized environments to locate which
container has lost a process.  Now that we have a single line for the oom
context, we can trivially add both the oom memcg (this can be either
global_oom or a specific memcg which hits its hard limits) and task_memcg
which is the victim's memcg.

Below is the single line output in the oom report after this patch.

- global oom context information:

oom-kill:constraint=<constraint>,nodemask=<nodemask>,cpuset=<cpuset>,mems_allowed=<mems_allowed>,global_oom,task_memcg=<memcg>,task=<comm>,pid=<pid>,uid=<uid>

- memcg oom context information:

oom-kill:constraint=<constraint>,nodemask=<nodemask>,cpuset=<cpuset>,mems_allowed=<mems_allowed>,oom_memcg=<memcg>,task_memcg=<memcg>,task=<comm>,pid=<pid>,uid=<uid>

[penguin-kernel@I-love.SAKURA.ne.jp: use pr_cont() in mem_cgroup_print_oom_context()]
Link: http://lkml.kernel.org/r/201812190723.wBJ7NdkN032628@www262.sakura.ne.jp
Link: http://lkml.kernel.org/r/1542799799-36184-2-git-send-email-ufo19890607@gmail.com
Signed-off-by: yuzhoujian <yuzhoujian@didichuxing.com>
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: David Rientjes <rientjes@google.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Roman Gushchin <guro@fb.com>
Cc: Yang Shi <yang.s@alibaba-inc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm, oom: reorganize the oom report in dump_header
yuzhoujian [Fri, 28 Dec 2018 08:36:07 +0000 (00:36 -0800)]
mm, oom: reorganize the oom report in dump_header

OOM report contains several sections.  The first one is the allocation
context that has triggered the OOM.  Then we have cpuset context followed
by the stack trace of the OOM path.  The tird one is the OOM memory
information.  Followed by the current memory state of all system tasks.
At last, we will show oom eligible tasks and the information about the
chosen oom victim.

One thing that makes parsing more awkward than necessary is that we do not
have a single and easily parsable line about the oom context.  This patch
is reorganizing the oom report to

1) who invoked oom and what was the allocation request

[  515.902945] tuned invoked oom-killer: gfp_mask=0x6200ca(GFP_HIGHUSER_MOVABLE), order=0, oom_score_adj=0

2) OOM stack trace

[  515.904273] CPU: 24 PID: 1809 Comm: tuned Not tainted 4.20.0-rc3+ #3
[  515.905518] Hardware name: Inspur SA5212M4/YZMB-00370-107, BIOS 4.1.10 11/14/2016
[  515.906821] Call Trace:
[  515.908062]  dump_stack+0x5a/0x73
[  515.909311]  dump_header+0x55/0x28c
[  515.914260]  oom_kill_process+0x2d8/0x300
[  515.916708]  out_of_memory+0x145/0x4a0
[  515.917932]  __alloc_pages_slowpath+0x7d2/0xa16
[  515.919157]  __alloc_pages_nodemask+0x277/0x290
[  515.920367]  filemap_fault+0x3d0/0x6c0
[  515.921529]  ? filemap_map_pages+0x2b8/0x420
[  515.922709]  ext4_filemap_fault+0x2c/0x40 [ext4]
[  515.923884]  __do_fault+0x20/0x80
[  515.925032]  __handle_mm_fault+0xbc0/0xe80
[  515.926195]  handle_mm_fault+0xfa/0x210
[  515.927357]  __do_page_fault+0x233/0x4c0
[  515.928506]  do_page_fault+0x32/0x140
[  515.929646]  ? page_fault+0x8/0x30
[  515.930770]  page_fault+0x1e/0x30

3) OOM memory information

[  515.958093] Mem-Info:
[  515.959647] active_anon:26501758 inactive_anon:1179809 isolated_anon:0
 active_file:4402672 inactive_file:483963 isolated_file:1344
 unevictable:0 dirty:4886753 writeback:0 unstable:0
 slab_reclaimable:148442 slab_unreclaimable:18741
 mapped:1347 shmem:1347 pagetables:58669 bounce:0
 free:88663 free_pcp:0 free_cma:0
...

4) current memory state of all system tasks

[  516.079544] [    744]     0   744     9211     1345   114688       82             0 systemd-journal
[  516.082034] [    787]     0   787    31764        0   143360       92             0 lvmetad
[  516.084465] [    792]     0   792    10930        1   110592      208         -1000 systemd-udevd
[  516.086865] [   1199]     0  1199    13866        0   131072      112         -1000 auditd
[  516.089190] [   1222]     0  1222    31990        1   110592      157             0 smartd
[  516.091477] [   1225]     0  1225     4864       85    81920       43             0 irqbalance
[  516.093712] [   1226]     0  1226    52612        0   258048      426             0 abrtd
[  516.112128] [   1280]     0  1280   109774       55   299008      400             0 NetworkManager
[  516.113998] [   1295]     0  1295    28817       37    69632       24             0 ksmtuned
[  516.144596] [  10718]     0 10718  2622484  1721372 15998976   267219             0 panic
[  516.145792] [  10719]     0 10719  2622484  1164767  9818112    53576             0 panic
[  516.146977] [  10720]     0 10720  2622484  1174361  9904128    53709             0 panic
[  516.148163] [  10721]     0 10721  2622484  1209070 10194944    54824             0 panic
[  516.149329] [  10722]     0 10722  2622484  1745799 14774272    91138             0 panic

5) oom context (contrains and the chosen victim).

oom-kill:constraint=CONSTRAINT_NONE,nodemask=(null),cpuset=/,mems_allowed=0-1,task=panic,pid=10737,uid=0

An admin can easily get the full oom context at a single line which
makes parsing much easier.

Link: http://lkml.kernel.org/r/1542799799-36184-1-git-send-email-ufo19890607@gmail.com
Signed-off-by: yuzhoujian <yuzhoujian@didichuxing.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: "Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Yang Shi <yang.s@alibaba-inc.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm: make free_reserved_area() return "const char *"
Alexey Dobriyan [Fri, 28 Dec 2018 08:36:03 +0000 (00:36 -0800)]
mm: make free_reserved_area() return "const char *"

and propagate through down the call stack.

Link: http://lkml.kernel.org/r/20181124091411.GC10969@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm/debug.c: make "migrate_reason_names[]" const char *
Alexey Dobriyan [Fri, 28 Dec 2018 08:35:59 +0000 (00:35 -0800)]
mm/debug.c: make "migrate_reason_names[]" const char *

Those strings are immutable as well.

Link: http://lkml.kernel.org/r/20181124090508.GB10877@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: David Hildenbrand <david@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm/mmzone.c: make "migratetype_names" const char *
Alexey Dobriyan [Fri, 28 Dec 2018 08:35:55 +0000 (00:35 -0800)]
mm/mmzone.c: make "migratetype_names" const char *

Those strings are immutable in fact.

Link: http://lkml.kernel.org/r/20181124090327.GA10877@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm: reclaim small amounts of memory when an external fragmentation event occurs
Mel Gorman [Fri, 28 Dec 2018 08:35:52 +0000 (00:35 -0800)]
mm: reclaim small amounts of memory when an external fragmentation event occurs

An external fragmentation event was previously described as

    When the page allocator fragments memory, it records the event using
    the mm_page_alloc_extfrag event. If the fallback_order is smaller
    than a pageblock order (order-9 on 64-bit x86) then it's considered
    an event that will cause external fragmentation issues in the future.

The kernel reduces the probability of such events by increasing the
watermark sizes by calling set_recommended_min_free_kbytes early in the
lifetime of the system.  This works reasonably well in general but if
there are enough sparsely populated pageblocks then the problem can still
occur as enough memory is free overall and kswapd stays asleep.

This patch introduces a watermark_boost_factor sysctl that allows a zone
watermark to be temporarily boosted when an external fragmentation causing
events occurs.  The boosting will stall allocations that would decrease
free memory below the boosted low watermark and kswapd is woken if the
calling context allows to reclaim an amount of memory relative to the size
of the high watermark and the watermark_boost_factor until the boost is
cleared.  When kswapd finishes, it wakes kcompactd at the pageblock order
to clean some of the pageblocks that may have been affected by the
fragmentation event.  kswapd avoids any writeback, slab shrinkage and swap
from reclaim context during this operation to avoid excessive system
disruption in the name of fragmentation avoidance.  Care is taken so that
kswapd will do normal reclaim work if the system is really low on memory.

This was evaluated using the same workloads as "mm, page_alloc: Spread
allocations across zones before introducing fragmentation".

1-socket Skylake machine
config-global-dhp__workload_thpfioscale XFS (no special madvise)
4 fio threads, 1 THP allocating thread
--------------------------------------

4.20-rc3 extfrag events < order 9:   804694
4.20-rc3+patch:                      408912 (49% reduction)
4.20-rc3+patch1-4:                    18421 (98% reduction)

                                   4.20.0-rc3             4.20.0-rc3
                                 lowzone-v5r8             boost-v5r8
Amean     fault-base-1      653.58 (   0.00%)      652.71 (   0.13%)
Amean     fault-huge-1        0.00 (   0.00%)      178.93 * -99.00%*

                              4.20.0-rc3             4.20.0-rc3
                            lowzone-v5r8             boost-v5r8
Percentage huge-1        0.00 (   0.00%)        5.12 ( 100.00%)

Note that external fragmentation causing events are massively reduced by
this path whether in comparison to the previous kernel or the vanilla
kernel.  The fault latency for huge pages appears to be increased but that
is only because THP allocations were successful with the patch applied.

1-socket Skylake machine
global-dhp__workload_thpfioscale-madvhugepage-xfs (MADV_HUGEPAGE)
-----------------------------------------------------------------

4.20-rc3 extfrag events < order 9:  291392
4.20-rc3+patch:                     191187 (34% reduction)
4.20-rc3+patch1-4:                   13464 (95% reduction)

thpfioscale Fault Latencies
                                   4.20.0-rc3             4.20.0-rc3
                                 lowzone-v5r8             boost-v5r8
Min       fault-base-1      912.00 (   0.00%)      905.00 (   0.77%)
Min       fault-huge-1      127.00 (   0.00%)      135.00 (  -6.30%)
Amean     fault-base-1     1467.55 (   0.00%)     1481.67 (  -0.96%)
Amean     fault-huge-1     1127.11 (   0.00%)     1063.88 *   5.61%*

                              4.20.0-rc3             4.20.0-rc3
                            lowzone-v5r8             boost-v5r8
Percentage huge-1       77.64 (   0.00%)       83.46 (   7.49%)

As before, massive reduction in external fragmentation events, some jitter
on latencies and an increase in THP allocation success rates.

2-socket Haswell machine
config-global-dhp__workload_thpfioscale XFS (no special madvise)
4 fio threads, 5 THP allocating threads
----------------------------------------------------------------

4.20-rc3 extfrag events < order 9:  215698
4.20-rc3+patch:                     200210 (7% reduction)
4.20-rc3+patch1-4:                   14263 (93% reduction)

                                   4.20.0-rc3             4.20.0-rc3
                                 lowzone-v5r8             boost-v5r8
Amean     fault-base-5     1346.45 (   0.00%)     1306.87 (   2.94%)
Amean     fault-huge-5     3418.60 (   0.00%)     1348.94 (  60.54%)

                              4.20.0-rc3             4.20.0-rc3
                            lowzone-v5r8             boost-v5r8
Percentage huge-5        0.78 (   0.00%)        7.91 ( 910.64%)

There is a 93% reduction in fragmentation causing events, there is a big
reduction in the huge page fault latency and allocation success rate is
higher.

2-socket Haswell machine
global-dhp__workload_thpfioscale-madvhugepage-xfs (MADV_HUGEPAGE)
-----------------------------------------------------------------

4.20-rc3 extfrag events < order 9: 166352
4.20-rc3+patch:                    147463 (11% reduction)
4.20-rc3+patch1-4:                  11095 (93% reduction)

thpfioscale Fault Latencies
                                   4.20.0-rc3             4.20.0-rc3
                                 lowzone-v5r8             boost-v5r8
Amean     fault-base-5     6217.43 (   0.00%)     7419.67 * -19.34%*
Amean     fault-huge-5     3163.33 (   0.00%)     3263.80 (  -3.18%)

                              4.20.0-rc3             4.20.0-rc3
                            lowzone-v5r8             boost-v5r8
Percentage huge-5       95.14 (   0.00%)       87.98 (  -7.53%)

There is a large reduction in fragmentation events with some jitter around
the latencies and success rates.  As before, the high THP allocation
success rate does mean the system is under a lot of pressure.  However, as
the fragmentation events are reduced, it would be expected that the
long-term allocation success rate would be higher.

Link: http://lkml.kernel.org/r/20181123114528.28802-5-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Zi Yan <zi.yan@cs.rutgers.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm: use alloc_flags to record if kswapd can wake
Mel Gorman [Fri, 28 Dec 2018 08:35:48 +0000 (00:35 -0800)]
mm: use alloc_flags to record if kswapd can wake

This is a preparation patch that copies the GFP flag __GFP_KSWAPD_RECLAIM
into alloc_flags.  This is a preparation patch only that avoids having to
pass gfp_mask through a long callchain in a future patch.

Note that the setting in the fast path happens in alloc_flags_nofragment()
and it may be claimed that this has nothing to do with ALLOC_NO_FRAGMENT.
That's true in this patch but is not true later so it's done now for
easier review to show where the flag needs to be recorded.

No functional change.

[mgorman@techsingularity.net: ALLOC_KSWAPD flag needs to be applied in the !CONFIG_ZONE_DMA32 case]
Link: http://lkml.kernel.org/r/20181126143503.GO23260@techsingularity.net
Link: http://lkml.kernel.org/r/20181123114528.28802-4-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Zi Yan <zi.yan@cs.rutgers.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm: move zone watermark accesses behind an accessor
Mel Gorman [Fri, 28 Dec 2018 08:35:44 +0000 (00:35 -0800)]
mm: move zone watermark accesses behind an accessor

This is a preparation patch only, no functional change.

Link: http://lkml.kernel.org/r/20181123114528.28802-3-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Zi Yan <zi.yan@cs.rutgers.edu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm, page_alloc: spread allocations across zones before introducing fragmentation
Mel Gorman [Fri, 28 Dec 2018 08:35:41 +0000 (00:35 -0800)]
mm, page_alloc: spread allocations across zones before introducing fragmentation

Patch series "Fragmentation avoidance improvements", v5.

It has been noted before that fragmentation avoidance (aka
anti-fragmentation) is not perfect. Given sufficient time or an adverse
workload, memory gets fragmented and the long-term success of high-order
allocations degrades. This series defines an adverse workload, a definition
of external fragmentation events (including serious) ones and a series
that reduces the level of those fragmentation events.

The details of the workload and the consequences are described in more
detail in the changelogs. However, from patch 1, this is a high-level
summary of the adverse workload. The exact details are found in the
mmtests implementation.

The broad details of the workload are as follows;

1. Create an XFS filesystem (not specified in the configuration but done
   as part of the testing for this patch)
2. Start 4 fio threads that write a number of 64K files inefficiently.
   Inefficiently means that files are created on first access and not
   created in advance (fio parameterr create_on_open=1) and fallocate
   is not used (fallocate=none). With multiple IO issuers this creates
   a mix of slab and page cache allocations over time. The total size
   of the files is 150% physical memory so that the slabs and page cache
   pages get mixed
3. Warm up a number of fio read-only threads accessing the same files
   created in step 2. This part runs for the same length of time it
   took to create the files. It'll fault back in old data and further
   interleave slab and page cache allocations. As it's now low on
   memory due to step 2, fragmentation occurs as pageblocks get
   stolen.
4. While step 3 is still running, start a process that tries to allocate
   75% of memory as huge pages with a number of threads. The number of
   threads is based on a (NR_CPUS_SOCKET - NR_FIO_THREADS)/4 to avoid THP
   threads contending with fio, any other threads or forcing cross-NUMA
   scheduling. Note that the test has not been used on a machine with less
   than 8 cores. The benchmark records whether huge pages were allocated
   and what the fault latency was in microseconds
5. Measure the number of events potentially causing external fragmentation,
   the fault latency and the huge page allocation success rate.
6. Cleanup

Overall the series reduces external fragmentation causing events by over 94%
on 1 and 2 socket machines, which in turn impacts high-order allocation
success rates over the long term. There are differences in latencies and
high-order allocation success rates. Latencies are a mixed bag as they
are vulnerable to exact system state and whether allocations succeeded
so they are treated as a secondary metric.

Patch 1 uses lower zones if they are populated and have free memory
instead of fragmenting a higher zone. It's special cased to
handle a Normal->DMA32 fallback with the reasons explained
in the changelog.

Patch 2-4 boosts watermarks temporarily when an external fragmentation
event occurs. kswapd wakes to reclaim a small amount of old memory
and then wakes kcompactd on completion to recover the system
slightly. This introduces some overhead in the slowpath. The level
of boosting can be tuned or disabled depending on the tolerance
for fragmentation vs allocation latency.

Patch 5 stalls some movable allocation requests to let kswapd from patch 4
make some progress. The duration of the stalls is very low but it
is possible to tune the system to avoid fragmentation events if
larger stalls can be tolerated.

The bulk of the improvement in fragmentation avoidance is from patches
1-4 but patch 5 can deal with a rare corner case and provides the option
of tuning a system for THP allocation success rates in exchange for
some stalls to control fragmentation.

This patch (of 5):

The page allocator zone lists are iterated based on the watermarks of each
zone which does not take anti-fragmentation into account.  On x86, node 0
may have multiple zones while other nodes have one zone.  A consequence is
that tasks running on node 0 may fragment ZONE_NORMAL even though
ZONE_DMA32 has plenty of free memory.  This patch special cases the
allocator fast path such that it'll try an allocation from a lower local
zone before fragmenting a higher zone.  In this case, stealing of
pageblocks or orders larger than a pageblock are still allowed in the fast
path as they are uninteresting from a fragmentation point of view.

This was evaluated using a benchmark designed to fragment memory before
attempting THP allocations.  It's implemented in mmtests as the following
configurations

configs/config-global-dhp__workload_thpfioscale
configs/config-global-dhp__workload_thpfioscale-defrag
configs/config-global-dhp__workload_thpfioscale-madvhugepage

e.g. from mmtests
./run-mmtests.sh --run-monitor --config configs/config-global-dhp__workload_thpfioscale test-run-1

The broad details of the workload are as follows;

1. Create an XFS filesystem (not specified in the configuration but done
   as part of the testing for this patch).
2. Start 4 fio threads that write a number of 64K files inefficiently.
   Inefficiently means that files are created on first access and not
   created in advance (fio parameter create_on_open=1) and fallocate
   is not used (fallocate=none). With multiple IO issuers this creates
   a mix of slab and page cache allocations over time. The total size
   of the files is 150% physical memory so that the slabs and page cache
   pages get mixed.
3. Warm up a number of fio read-only processes accessing the same files
   created in step 2. This part runs for the same length of time it
   took to create the files. It'll refault old data and further
   interleave slab and page cache allocations. As it's now low on
   memory due to step 2, fragmentation occurs as pageblocks get
   stolen.
4. While step 3 is still running, start a process that tries to allocate
   75% of memory as huge pages with a number of threads. The number of
   threads is based on a (NR_CPUS_SOCKET - NR_FIO_THREADS)/4 to avoid THP
   threads contending with fio, any other threads or forcing cross-NUMA
   scheduling. Note that the test has not been used on a machine with less
   than 8 cores. The benchmark records whether huge pages were allocated
   and what the fault latency was in microseconds.
5. Measure the number of events potentially causing external fragmentation,
   the fault latency and the huge page allocation success rate.
6. Cleanup the test files.

Note that due to the use of IO and page cache that this benchmark is not
suitable for running on large machines where the time to fragment memory
may be excessive.  Also note that while this is one mix that generates
fragmentation that it's not the only mix that generates fragmentation.
Differences in workload that are more slab-intensive or whether SLUB is
used with high-order pages may yield different results.

When the page allocator fragments memory, it records the event using the
mm_page_alloc_extfrag ftrace event.  If the fallback_order is smaller than
a pageblock order (order-9 on 64-bit x86) then it's considered to be an
"external fragmentation event" that may cause issues in the future.
Hence, the primary metric here is the number of external fragmentation
events that occur with order < 9.  The secondary metric is allocation
latency and huge page allocation success rates but note that differences
in latencies and what the success rate also can affect the number of
external fragmentation event which is why it's a secondary metric.

1-socket Skylake machine
config-global-dhp__workload_thpfioscale XFS (no special madvise)
4 fio threads, 1 THP allocating thread
--------------------------------------

4.20-rc3 extfrag events < order 9:   804694
4.20-rc3+patch:                      408912 (49% reduction)

thpfioscale Fault Latencies
                                   4.20.0-rc3             4.20.0-rc3
                                      vanilla           lowzone-v5r8
Amean     fault-base-1      662.92 (   0.00%)      653.58 *   1.41%*
Amean     fault-huge-1        0.00 (   0.00%)        0.00 (   0.00%)

                              4.20.0-rc3             4.20.0-rc3
                                 vanilla           lowzone-v5r8
Percentage huge-1        0.00 (   0.00%)        0.00 (   0.00%)

Fault latencies are slightly reduced while allocation success rates remain
at zero as this configuration does not make any special effort to allocate
THP and fio is heavily active at the time and either filling memory or
keeping pages resident.  However, a 49% reduction of serious fragmentation
events reduces the changes of external fragmentation being a problem in
the future.

Vlastimil asked during review for a breakdown of the allocation types
that are falling back.

vanilla
   3816 MIGRATE_UNMOVABLE
 800845 MIGRATE_MOVABLE
     33 MIGRATE_UNRECLAIMABLE

patch
    735 MIGRATE_UNMOVABLE
 408135 MIGRATE_MOVABLE
     42 MIGRATE_UNRECLAIMABLE

The majority of the fallbacks are due to movable allocations and this is
consistent for the workload throughout the series so will not be presented
again as the primary source of fallbacks are movable allocations.

Movable fallbacks are sometimes considered "ok" to fallback because they
can be migrated.  The problem is that they can fill an
unmovable/reclaimable pageblock causing those allocations to fallback
later and polluting pageblocks with pages that cannot move.  If there is a
movable fallback, it is pretty much guaranteed to affect an
unmovable/reclaimable pageblock and while it might not be enough to
actually cause a unmovable/reclaimable fallback in the future, we cannot
know that in advance so the patch takes the only option available to it.
Hence, it's important to control them.  This point is also consistent
throughout the series and will not be repeated.

1-socket Skylake machine
global-dhp__workload_thpfioscale-madvhugepage-xfs (MADV_HUGEPAGE)
-----------------------------------------------------------------

4.20-rc3 extfrag events < order 9:  291392
4.20-rc3+patch:                     191187 (34% reduction)

thpfioscale Fault Latencies
                                   4.20.0-rc3             4.20.0-rc3
                                      vanilla           lowzone-v5r8
Amean     fault-base-1     1495.14 (   0.00%)     1467.55 (   1.85%)
Amean     fault-huge-1     1098.48 (   0.00%)     1127.11 (  -2.61%)

thpfioscale Percentage Faults Huge
                              4.20.0-rc3             4.20.0-rc3
                                 vanilla           lowzone-v5r8
Percentage huge-1       78.57 (   0.00%)       77.64 (  -1.18%)

Fragmentation events were reduced quite a bit although this is known
to be a little variable. The latencies and allocation success rates
are similar but they were already quite high.

2-socket Haswell machine
config-global-dhp__workload_thpfioscale XFS (no special madvise)
4 fio threads, 5 THP allocating threads
----------------------------------------------------------------

4.20-rc3 extfrag events < order 9:  215698
4.20-rc3+patch:                     200210 (7% reduction)

thpfioscale Fault Latencies
                                   4.20.0-rc3             4.20.0-rc3
                                      vanilla           lowzone-v5r8
Amean     fault-base-5     1350.05 (   0.00%)     1346.45 (   0.27%)
Amean     fault-huge-5     4181.01 (   0.00%)     3418.60 (  18.24%)

                              4.20.0-rc3             4.20.0-rc3
                                 vanilla           lowzone-v5r8
Percentage huge-5        1.15 (   0.00%)        0.78 ( -31.88%)

The reduction of external fragmentation events is slight and this is
partially due to the removal of __GFP_THISNODE in commit ac5b2c18911f
("mm: thp: relax __GFP_THISNODE for MADV_HUGEPAGE mappings") as THP
allocations can now spill over to remote nodes instead of fragmenting
local memory.

2-socket Haswell machine
global-dhp__workload_thpfioscale-madvhugepage-xfs (MADV_HUGEPAGE)
-----------------------------------------------------------------

4.20-rc3 extfrag events < order 9: 166352
4.20-rc3+patch:                    147463 (11% reduction)

thpfioscale Fault Latencies
                                   4.20.0-rc3             4.20.0-rc3
                                      vanilla           lowzone-v5r8
Amean     fault-base-5     6138.97 (   0.00%)     6217.43 (  -1.28%)
Amean     fault-huge-5     2294.28 (   0.00%)     3163.33 * -37.88%*

thpfioscale Percentage Faults Huge
                              4.20.0-rc3             4.20.0-rc3
                                 vanilla           lowzone-v5r8
Percentage huge-5       96.82 (   0.00%)       95.14 (  -1.74%)

There was a slight reduction in external fragmentation events although the
latencies were higher.  The allocation success rate is high enough that
the system is struggling and there is quite a lot of parallel reclaim and
compaction activity.  There is also a certain degree of luck on whether
processes start on node 0 or not for this patch but the relevance is
reduced later in the series.

Overall, the patch reduces the number of external fragmentation causing
events so the success of THP over long periods of time would be improved
for this adverse workload.

Link: http://lkml.kernel.org/r/20181123114528.28802-2-mgorman@techsingularity.net
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: David Rientjes <rientjes@google.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Zi Yan <zi.yan@cs.rutgers.edu>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm/memory_hotplug: drop "online" parameter from add_memory_resource()
David Hildenbrand [Fri, 28 Dec 2018 08:35:36 +0000 (00:35 -0800)]
mm/memory_hotplug: drop "online" parameter from add_memory_resource()

Userspace should always be in charge of how to online memory and if memory
should be onlined automatically in the kernel.  Let's drop the parameter
to overwrite this - XEN passes memhp_auto_online, just like add_memory(),
so we can directly use that instead internally.

Link: http://lkml.kernel.org/r/20181123123740.27652-1-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Acked-by: Juergen Gross <jgross@suse.com>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Stefano Stabellini <sstabellini@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Pavel Tatashin <pasha.tatashin@oracle.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Arun KS <arunks@codeaurora.org>
Cc: Mathieu Malaterre <malat@debian.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agodrivers/base/memory.c: remove an unnecessary check on NR_MEM_SECTIONS
Wei Yang [Fri, 28 Dec 2018 08:35:33 +0000 (00:35 -0800)]
drivers/base/memory.c: remove an unnecessary check on NR_MEM_SECTIONS

In cb5e39b8038b ("drivers: base: refactor add_memory_section() to
add_memory_block()"), add_memory_block() is introduced, which is only
invoked in memory_dev_init().

When combining these two loops in memory_dev_init() and
add_memory_block(), they looks like this:

    for (i = 0; i < NR_MEM_SECTIONS; i += sections_per_block)
        for (j = i;
    (j < i + sections_per_block) && j < NR_MEM_SECTIONS;
    j++)

Since it is sure the (i < NR_MEM_SECTIONS) and j sits in its own memory
block, the check of (j < NR_MEM_SECTIONS) is not necessary.

This patch just removes this check.

Link: http://lkml.kernel.org/r/20181123222811.18216-1-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Cc: Seth Jennings <sjenning@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomemblock: replace usage of __memblock_free_early() with memblock_free()
Mike Rapoport [Fri, 28 Dec 2018 08:35:29 +0000 (00:35 -0800)]
memblock: replace usage of __memblock_free_early() with memblock_free()

__memblock_free_early() is only used by the convenience wrappers, so
essentially we wrap a call to memblock_free() twice.  Replace calls of
__memblock_free_early() with calls to memblock_free() and drop the former.

Link: http://lkml.kernel.org/r/20181125102940.GE28634@rapoport-lnx
Signed-off-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Wentao Wang <witallwang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm/page_alloc.c: deduplicate __memblock_free_early() and memblock_free()
Wentao Wang [Fri, 28 Dec 2018 08:35:26 +0000 (00:35 -0800)]
mm/page_alloc.c: deduplicate __memblock_free_early() and memblock_free()

Link: http://lkml.kernel.org/r/C8ECE1B7A767434691FEEFA3A01765D72AFB8E78@MX203CL03.corp.emc.com
Signed-off-by: Wentao Wang <witallwang@gmail.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm/page_alloc.c: use a single function to free page
Aaron Lu [Fri, 28 Dec 2018 08:35:22 +0000 (00:35 -0800)]
mm/page_alloc.c: use a single function to free page

There are multiple places of freeing a page, they all do the same things
so a common function can be used to reduce code duplicate.

It also avoids bug fixed in one function but left in another.

Link: http://lkml.kernel.org/r/20181119134834.17765-3-aaron.lu@intel.com
Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Cc: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Cc: Jesper Dangaard Brouer <brouer@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Pankaj gupta <pagupta@redhat.com>
Cc: Pawel Staszewski <pstaszewski@itcare.pl>
Cc: Tariq Toukan <tariqt@mellanox.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm/page_alloc.c: free order-0 pages through PCP in page_frag_free()
Aaron Lu [Fri, 28 Dec 2018 08:35:18 +0000 (00:35 -0800)]
mm/page_alloc.c: free order-0 pages through PCP in page_frag_free()

page_frag_free() calls __free_pages_ok() to free the page back to Buddy.
This is OK for high order page, but for order-0 pages, it misses the
optimization opportunity of using Per-Cpu-Pages and can cause zone lock
contention when called frequently.

Pawel Staszewski recently shared his result of 'how Linux kernel handles
normal traffic'[1] and from perf data, Jesper Dangaard Brouer found the
lock contention comes from page allocator:

  mlx5e_poll_tx_cq
  |
   --16.34%--napi_consume_skb
             |
             |--12.65%--__free_pages_ok
             |          |
             |           --11.86%--free_one_page
             |                     |
             |                     |--10.10%--queued_spin_lock_slowpath
             |                     |
             |                      --0.65%--_raw_spin_lock
             |
             |--1.55%--page_frag_free
             |
              --1.44%--skb_release_data

Jesper explained how it happened: mlx5 driver RX-page recycle mechanism is
not effective in this workload and pages have to go through the page
allocator.  The lock contention happens during mlx5 DMA TX completion
cycle.  And the page allocator cannot keep up at these speeds.[2]

I thought that __free_pages_ok() are mostly freeing high order pages and
thought this is an lock contention for high order pages but Jesper
explained in detail that __free_pages_ok() here are actually freeing
order-0 pages because mlx5 is using order-0 pages to satisfy its page pool
allocation request.[3]

The free path as pointed out by Jesper is:
skb_free_head()
  -> skb_free_frag()
    -> page_frag_free()
And the pages being freed on this path are order-0 pages.

Fix this by doing similar things as in __page_frag_cache_drain() - send
the being freed page to PCP if it's an order-0 page, or directly to Buddy
if it is a high order page.

With this change, Paweł hasn't noticed lock contention yet in his
workload and Jesper has noticed a 7% performance improvement using a micro
benchmark and lock contention is gone.  Ilias' test on a 'low' speed 1Gbit
interface on an cortex-a53 shows ~11% performance boost testing with
64byte packets and __free_pages_ok() disappeared from perf top.

[1]: https://www.spinics.net/lists/netdev/msg531362.html
[2]: https://www.spinics.net/lists/netdev/msg531421.html
[3]: https://www.spinics.net/lists/netdev/msg531556.html

[akpm@linux-foundation.org: add comment]
Link: http://lkml.kernel.org/r/20181120014544.GB10657@intel.com
Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Reported-by: Pawel Staszewski <pstaszewski@itcare.pl>
Analysed-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Tested-by: Ilias Apalodimas <ilias.apalodimas@linaro.org>
Acked-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Acked-by: Tariq Toukan <tariqt@mellanox.com>
Acked-by: Pankaj gupta <pagupta@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm, hmm: mark hmm_devmem_{add, add_resource} EXPORT_SYMBOL_GPL
Dan Williams [Fri, 28 Dec 2018 08:35:15 +0000 (00:35 -0800)]
mm, hmm: mark hmm_devmem_{add, add_resource} EXPORT_SYMBOL_GPL

At Maintainer Summit, Greg brought up a topic I proposed around
EXPORT_SYMBOL_GPL usage.  The motivation was considerations for when
EXPORT_SYMBOL_GPL is warranted and the criteria for taking the exceptional
step of reclassifying an existing export.  Specifically, I wanted to make
the case that although the line is fuzzy and hard to specify in abstract
terms, it is nonetheless clear that devm_memremap_pages() and HMM
(Heterogeneous Memory Management) have crossed it.  The
devm_memremap_pages() facility should have been EXPORT_SYMBOL_GPL from the
beginning, and HMM as a derivative of that functionality should have
naturally picked up that designation as well.

Contrary to typical rules, the HMM infrastructure was merged upstream with
zero in-tree consumers.  There was a promise at the time that those users
would be merged "soon", but it has been over a year with no drivers
arriving.  While the Nouveau driver is about to belatedly make good on
that promise it is clear that HMM was targeted first and foremost at an
out-of-tree consumer.

HMM is derived from devm_memremap_pages(), a facility Christoph and I
spearheaded to support persistent memory.  It combines a device lifetime
model with a dynamically created 'struct page' / memmap array for any
physical address range.  It enables coordination and control of the many
code paths in the kernel built to interact with memory via 'struct page'
objects.  With HMM the integration goes even deeper by allowing device
drivers to hook and manipulate page fault and page free events.

One interpretation of when EXPORT_SYMBOL is suitable is when it is
exporting stable and generic leaf functionality.  The
devm_memremap_pages() facility continues to see expanding use cases,
peer-to-peer DMA being the most recent, with no clear end date when it
will stop attracting reworks and semantic changes.  It is not suitable to
export devm_memremap_pages() as a stable 3rd party driver API due to the
fact that it is still changing and manipulates core behavior.  Moreover,
it is not in the best interest of the long term development of the core
memory management subsystem to permit any external driver to effectively
define its own system-wide memory management policies with no
encouragement to engage with upstream.

I am also concerned that HMM was designed in a way to minimize further
engagement with the core-MM.  That, with these hooks in place,
device-drivers are free to implement their own policies without much
consideration for whether and how the core-MM could grow to meet that
need.  Going forward not only should HMM be EXPORT_SYMBOL_GPL, but the
core-MM should be allowed the opportunity and stimulus to change and
address these new use cases as first class functionality.

Original changelog:

hmm_devmem_add(), and hmm_devmem_add_resource() duplicated
devm_memremap_pages() and are now simple now wrappers around the core
facility to inject a dev_pagemap instance into the global pgmap_radix and
hook page-idle events.  The devm_memremap_pages() interface is base
infrastructure for HMM.  HMM has more and deeper ties into the kernel
memory management implementation than base ZONE_DEVICE which is itself a
EXPORT_SYMBOL_GPL facility.

Originally, the HMM page structure creation routines copied the
devm_memremap_pages() code and reused ZONE_DEVICE.  A cleanup to unify the
implementations was discussed during the initial review:
http://lkml.iu.edu/hypermail/linux/kernel/1701.2/00812.html Recent work to
extend devm_memremap_pages() for the peer-to-peer-DMA facility enabled
this cleanup to move forward.

In addition to the integration with devm_memremap_pages() HMM depends on
other GPL-only symbols:

    mmu_notifier_unregister_no_release
    percpu_ref
    region_intersects
    __class_create

It goes further to consume / indirectly expose functionality that is not
exported to any other driver:

    alloc_pages_vma
    walk_page_range

HMM is derived from devm_memremap_pages(), and extends deep core-kernel
fundamentals. Similar to devm_memremap_pages(), mark its entry points
EXPORT_SYMBOL_GPL().

[logang@deltatee.com: PCI/P2PDMA: match interface changes to devm_memremap_pages()]
Link: http://lkml.kernel.org/r/20181130225911.2900-1-logang@deltatee.com
Link: http://lkml.kernel.org/r/154275560565.76910.15919297436557795278.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: "Jérôme Glisse" <jglisse@redhat.com>
Cc: Balbir Singh <bsingharora@gmail.com>,
Cc: Michal Hocko <mhocko@suse.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm, hmm: replace hmm_devmem_pages_create() with devm_memremap_pages()
Dan Williams [Fri, 28 Dec 2018 08:35:11 +0000 (00:35 -0800)]
mm, hmm: replace hmm_devmem_pages_create() with devm_memremap_pages()

Commit e8d513483300 ("memremap: change devm_memremap_pages interface to
use struct dev_pagemap") refactored devm_memremap_pages() to allow a
dev_pagemap instance to be supplied.  Passing in a dev_pagemap interface
simplifies the design of pgmap type drivers in that they can rely on
container_of() to lookup any private data associated with the given
dev_pagemap instance.

In addition to the cleanups this also gives hmm users multi-order-radix
improvements that arrived with commit ab1b597ee0e4 "mm,
devm_memremap_pages: use multi-order radix for ZONE_DEVICE lookups"

As part of the conversion to the devm_memremap_pages() method of
handling the percpu_ref relative to when pages are put, the percpu_ref
completion needs to move to hmm_devmem_ref_exit().  See 71389703839e
("mm, zone_device: Replace {get, put}_zone_device_page...") for details.

Link: http://lkml.kernel.org/r/154275560053.76910.10870962637383152392.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jérôme Glisse <jglisse@redhat.com>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm, hmm: use devm semantics for hmm_devmem_{add, remove}
Dan Williams [Fri, 28 Dec 2018 08:35:07 +0000 (00:35 -0800)]
mm, hmm: use devm semantics for hmm_devmem_{add, remove}

devm semantics arrange for resources to be torn down when
device-driver-probe fails or when device-driver-release completes.
Similar to devm_memremap_pages() there is no need to support an explicit
remove operation when the users properly adhere to devm semantics.

Note that devm_kzalloc() automatically handles allocating node-local
memory.

Link: http://lkml.kernel.org/r/154275559545.76910.9186690723515469051.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jérôme Glisse <jglisse@redhat.com>
Cc: "Jérôme Glisse" <jglisse@redhat.com>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm, devm_memremap_pages: add MEMORY_DEVICE_PRIVATE support
Dan Williams [Fri, 28 Dec 2018 08:35:01 +0000 (00:35 -0800)]
mm, devm_memremap_pages: add MEMORY_DEVICE_PRIVATE support

In preparation for consolidating all ZONE_DEVICE enabling via
devm_memremap_pages(), teach it how to handle the constraints of
MEMORY_DEVICE_PRIVATE ranges.

[jglisse@redhat.com: call move_pfn_range_to_zone for MEMORY_DEVICE_PRIVATE]
Link: http://lkml.kernel.org/r/154275559036.76910.12434636179931292607.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Jérôme Glisse <jglisse@redhat.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Reported-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm, devm_memremap_pages: fix shutdown handling
Dan Williams [Fri, 28 Dec 2018 08:34:57 +0000 (00:34 -0800)]
mm, devm_memremap_pages: fix shutdown handling

The last step before devm_memremap_pages() returns success is to allocate
a release action, devm_memremap_pages_release(), to tear the entire setup
down.  However, the result from devm_add_action() is not checked.

Checking the error from devm_add_action() is not enough.  The api
currently relies on the fact that the percpu_ref it is using is killed by
the time the devm_memremap_pages_release() is run.  Rather than continue
this awkward situation, offload the responsibility of killing the
percpu_ref to devm_memremap_pages_release() directly.  This allows
devm_memremap_pages() to do the right thing relative to init failures and
shutdown.

Without this change we could fail to register the teardown of
devm_memremap_pages().  The likelihood of hitting this failure is tiny as
small memory allocations almost always succeed.  However, the impact of
the failure is large given any future reconfiguration, or disable/enable,
of an nvdimm namespace will fail forever as subsequent calls to
devm_memremap_pages() will fail to setup the pgmap_radix since there will
be stale entries for the physical address range.

An argument could be made to require that the ->kill() operation be set in
the @pgmap arg rather than passed in separately.  However, it helps code
readability, tracking the lifetime of a given instance, to be able to grep
the kill routine directly at the devm_memremap_pages() call site.

Link: http://lkml.kernel.org/r/154275558526.76910.7535251937849268605.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Fixes: e8d513483300 ("memremap: change devm_memremap_pages interface...")
Reviewed-by: "Jérôme Glisse" <jglisse@redhat.com>
Reported-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm, devm_memremap_pages: kill mapping "System RAM" support
Dan Williams [Fri, 28 Dec 2018 08:34:54 +0000 (00:34 -0800)]
mm, devm_memremap_pages: kill mapping "System RAM" support

Given the fact that devm_memremap_pages() requires a percpu_ref that is
torn down by devm_memremap_pages_release() the current support for mapping
RAM is broken.

Support for remapping "System RAM" has been broken since the beginning and
there is no existing user of this this code path, so just kill the support
and make it an explicit error.

This cleanup also simplifies a follow-on patch to fix the error path when
setting a devm release action for devm_memremap_pages_release() fails.

Link: http://lkml.kernel.org/r/154275557997.76910.14689813630968180480.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: "Jérôme Glisse" <jglisse@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm, devm_memremap_pages: mark devm_memremap_pages() EXPORT_SYMBOL_GPL
Dan Williams [Fri, 28 Dec 2018 08:34:50 +0000 (00:34 -0800)]
mm, devm_memremap_pages: mark devm_memremap_pages() EXPORT_SYMBOL_GPL

devm_memremap_pages() is a facility that can create struct page entries
for any arbitrary range and give drivers the ability to subvert core
aspects of page management.

Specifically the facility is tightly integrated with the kernel's memory
hotplug functionality.  It injects an altmap argument deep into the
architecture specific vmemmap implementation to allow allocating from
specific reserved pages, and it has Linux specific assumptions about page
structure reference counting relative to get_user_pages() and
get_user_pages_fast().  It was an oversight and a mistake that this was
not marked EXPORT_SYMBOL_GPL from the outset.

Again, devm_memremap_pagex() exposes and relies upon core kernel internal
assumptions and will continue to evolve along with 'struct page', memory
hotplug, and support for new memory types / topologies.  Only an in-kernel
GPL-only driver is expected to keep up with this ongoing evolution.  This
interface, and functionality derived from this interface, is not suitable
for kernel-external drivers.

Link: http://lkml.kernel.org/r/154275557457.76910.16923571232582744134.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: "Jérôme Glisse" <jglisse@redhat.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
19 months agomm/page_alloc.c: change the order of MIGRATE_RECLAIMABLE/MIGRATE_MOVABLE in fallbacks
Huang Shijie [Fri, 28 Dec 2018 08:34:46 +0000 (00:34 -0800)]
mm/page_alloc.c: change the order of MIGRATE_RECLAIMABLE/MIGRATE_MOVABLE in fallbacks

In the enum migratetype definition, MIGRATE_MOVABLE is before
MIGRATE_RECLAIMABLE.  Change the order of them to match the enumeration's
order.

Link: http://lkml.kernel.org/r/20181121085821.3442-1-sjhuang@iluvatar.ai
Signed-off-by: Huang Shijie <sjhuang@iluvatar.ai>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>